The Urban Aquaculture Manual

by Jonathan Woods

Sponsored by Heifer Project Internationalwith assistance from the Evangelical Lutheran Church of America

 

 

Chapter Two

 

A Simple Recirculation System

 

 

 

INTRODUCTION

 

This chapter describes how to build a simple, inexpensive and compact aquaculture system. It fits Into a four foot by four foot space, runs off of one double-outlet air pump, and is easy to maintain. This is an ideal system to learn about aquaculture without spending a lot of money. The system described in this chapter has been built by ordinary people living in Toronto, Chicago, Little Rock, and Milwaukee. They didn't know much about aquaculture or even plumbing, but they shared a willigness to try something new and were successful.

 

HOW THE SYSTEM WORKS

 

The following is a quick account of the processes that occur in this recirculating system. Look for sources of additional information about how such systems work in the Resources Chapter.

This system mimics natural cycles. The sun (or artificial light) shines into the plant tank, causing aquatic plants and algae to grow These plants and algae flow into the fish tank (or are cut and fed) where herbivorous fish cat them. After digestion, the fish excrete ammonia (a sort of urine) and produce feces. These are partially broken down by snails and other invertebrates in the bottom of the fish tank and then pumped 'into the b1ofilter tank.

In the biofilter tank, specialized bacteria break down toxic ammonia into fairly harmless nitrates, which can be taken up by plants. Other bacteria and micro-organisms break down other waste products into forms that plants can use. Particles of waste are trapped by rocks and shells where they are eaten by invertebrates or broken down by other microorganisms. This tank acts like an aquatic compost pile, converting wastes into fertilizer for the plants.

 

 

Finally, the fertilized water flows into the plant tank, where it is taken up and converted into plant tissues. Submerged plants and algae add oxygen to the water when the sun shines. Clean water, oxygen, and green plant food flow into the fish tank, completing the cycle.

 

SITE

 

This system should be located in a warm sunny spot with a water source and drain nearby. It should sit on a strong floor that is level, and should be protected from vandalism and curious hands.

 

It is very important that the system is level. If not, the air-lift pumping system will not work well. Most houses and buildings are built with level floors - test the floor with a level or put a marble down and see if It rolls. If working on bare ground, try to tamp the earth down with a board where the system will go. This will prevent compression and uneven settling. A good idea is to put the system on top of a piece of plywood or a pallet.

 

PARTS AND TOOLS NEEDED

 

 

Hardware

 

3 - 55 gallon plastic barrels. These should he food grade (i.e , no chemical residues) and at least one should be semi-transparent.

1 - 10' long piece of 2" PVC pipe.

6 - 2" male adapters.

6 - 2" female adapters

.

3 - 2" tee (T) fittings.

 

3 - 2" L fittings.

1- aquarium air pump with double air outlet. Get a medium-sized one (e.g. the Elite 802 which produces 2500 cc/min. of air at 4.0 PSI)

2 - aquarium air stones.

1 - 10' long piece of aquarium air tubing (1/4" clear polyethylene).

several clean rags.

1 small can of PVC primer.

1 small can of PVC cement.

1 roll Teflon (plumbers) tape.

1 - tube of clear silicon sealant (bathroom or aquarium grade). Be sure that it is true silicon sealant, as synthetic sealants can be toxic.

several small pieces of window screen, preferably plastic, to cover pipes and prevent fish from escaping

2 - strong elastic bands.

40 gallons of crushed rock, brick, gravel, or other coarse rock-like material, washed to remove dirt and pollution. The pieces should range In size from 1/2" to several inches in diameter. Try to avoid pieces smaller than 1/2".

1 - 2' by 2' square piece of burlap or other strong, coarse cloth

10 gallons of oyster shells or dolomite, making sure that most of the pieces are larger than 1/2".

Tools

saw - to remove tops from the barrels and cut pipe. A Skill Saw (or "Jigsaw")

is probably the best for removing the tops, but a hand saw works well for cutting pipe.

scrub brush or sponge for cleaning up barrels and pipe

sandpaper or a small file for removing burrs from cut edges

felt pen to mark the barrels and pipe for cuts

power drill for drilling through-hulls

 

1/4" drill bit for making holes in filter in Pipe

2 1/4" hole saw (large bore drill bit) to drill holes for through hulls

 

caulking gun

2 pipe wrenches or large pliers - for tightening through-hulls (optional)

scissors - to cut plastic screen and burlap

Biological Materials

buckets of water (with some bottom mud or sand) from local lakes, rivers or ponds

1 quart of fresh compost

1 quart of good garden soil

1 quart of soil from a forest

1 quart of soil from a meadow

20-30 snails from an aquarium store or local pond

floating plants such as water lettuce or water hyacinth

20 - 30 fish fingerlings (nile tiapla are recommended)

 

CONSTRUCTION PROCEDURE

 

Most of this system can be built in two days if you can get all the materials together. Washing and leaching the barrels takes several days to do properly, so plan to do this before the actual construction. It is a good idea to let the system stabilize for a few days before adding any fish,

so arrange for the fingerlings to be delivered a week or so after you are finished building. Be sure to read ALL the instructions CAREFULLY before starting to build so that you know what has to be done next.

 

 

STEP 1. Rinsing the barrels.

You can obtain empty 200-litre food grade polyethylene barrels from food factories, breweries, recycyling centers, and many other places. Big cities often have dealers who buy and sell used barrels, or you could call your local recycyling organization. Rinse out the three barrels with a garden hose. Even food-grade barrels could contain toxins, so you should always handle them with care. Wear gloves, long sleeved shirts, long pants, and safety glasses when rinsing. You can drain them by tipping them over (hard) or using a sipihon (easier).

STEP 2. Leaching the barrels.

Leach the barrels. Barrels can be leached by filling them with water, letting them sit overnight, and then draining them the next day. Do this several times, using hot water if available. This will draw out any rest 'dues that have been absorbed by the plastic and may be harmful to fish.

STEP 3. Cutting the lids out of the barrels.

Cut out the lids of the barrels, leaving the rim intact. The rim provides support for the barrel, so it Is important not to cut it off There are several ways of cutting the lid out, depending on what tools you have. You can drill a small hole and then use a skill saw, or you can drill holes all the way around if you don't have a saw.

 

STEP 4. Washing the barrels.

Wash the barrels. Use soap, warm water, and a scrub brush or sponge. You should wear rubber gloves to protect your hands as well as a long sleeved shirt. You could use a mop, or take the barrel to a commercial car wash where you can use their pressure washer. Rinse off the soap, re-fill with water, and let them leach overnight again.

STEP 5. Placing the barrels and marking the through-hulls.

Arrange the barrels into a triangle on the site you have chosen. Using the felt pen, mark each barrel at the point where it is closest to the other two. Now measure six inches (6") straight down from each point and draw a cross mark. This will be where you drill the- holes for the connecting pipes.

Each barrel should have two crosses. Double check your measurements by measuring from the cross mark to the floor. All the cross marks should be the same distance from the floor.

Put the barrels back into the original triangle. Eyeball the crosses to make with sure they line up. Water will not practice circulate well if the crosses are not at quite the, same level.

STEP 6. Drilling the through-hulls.

Check the 2 1/4" large-bore drill bit against a male adapter. The bit should be slightly narrower than the threads of the adapter. That way the adapter can be screwed into the hole you drill, ensuring a snug fit. Straddle the barrel like youíre riding a horse, or get somebody else to. Carefully drill a hole, using the cross mark center. Remember to hold the drill straight up and down and lower it slowly. Bracing the drill with your other hand will help you cut an even, clean hole.

You can practice drilling holes through the lids you removed in STEP 3. Even if you are handy a drill, it is still a good idea to drilling because plastic drills differently from wood.

STEP 7. Connector pipe assembly.

Make the connector pipes by cutting three 3" long pieces of 2" pipe. Try to cut the pipe as square as possible. Use a knife and some sandpaper to

smooth the cut edges. Dry fit (i.e. put together without using cement) a connector piece of pipe between two male adapters. You should be able to see a little bit of the pipe in between the adapters when it is pushed into them as far as possible. Make two more sets from the remaining 3" long pieces of pipe and the male adapters.

STEP 8. Through-hull assembly.

Assemble the through-hull fitting as follows. First dry fit a male adapter through each hole, from the outside of the barrel in. Then GENTLY screw a female adapter onto each male adapter, but do not tighten at this point.

Put the other two connector pipes together by screwing them into the other two sets of holes. GENTLY screw on some female adapters. At this point, all the barrels in your system should be connected together 'in a triangle.

Now that all the pipe connectors and through-hulls have been put together, have a close look at the barrels. The barrels should be close together and level, and the three connectors should not be bent at funny angles or appear to be under stress. Check that the system is as you want it before you start cementing it together in the next step

STEP 9. Cementing the connector pipes.

WARNING: Primer and cement are dangerous chemicals. You should always wear rubber gloves and work in a well- ventilated area when using ' these chemicals. Be sure to read the ALL safety instructions on the cans before opening them!

Disassemble one of the connector pipes by unscrewing the male and female adapters and removing the connector pipe from between the two male adapters. You should have two male adapters, two female adapters and a 3" long piece of 2" pipe. Using a rag, wipe clean the inner surface of one of the male adapters and the outer surface of one end of the 3" long piece of pipe. Apply primer to all these surfaces and allow to dry.

Working quickly, apply PVC cement to the inside of the male adapters and the corresponding surface of the 3" long piece of pipe. Twist the pipe and the adapter together, making sure that you have pushed the pipe in as far as it will go. Wait for a few 11-11inutes until this joint sets, then cement the other male adapter to the other end of the connector pipe. Repeat this procedure for the other two sets of connector pipes and male adapters. Allow the cement to dry for 20 minutes before moving on to the next step.

STEP 10. Silicon sealing the through- hulls.

Silicon sealant can produce irritating fumes when used indoors. Be sure to ventilate your workspace as much as possible. Also, you should try not to get it on your skin or clothes, as it is very difficult to remove.

Take one of the connector pipe/male adapter sets that you made in STEP 9 and wrap several layers of Teflon tape around the threads of one of the adapters. Be sure to wrap the tape clockwise around the threads, otherwise it will bunch up. Generously cover the tape and threads with silicon sealant and twist the adapter through the hole in the barrel. Squirt a bit of silicon 'into the female adapter and begin to screw it onto the male adapter from inside the barrel. As you tighten, it will become harder and harder to turn the adapter and silicon will start to squeeze out from between the male and female adapters. Put on some work gloves to protect your hands and tighten the joint as much as you can. If you have a couple of pipe wrenches, then use them to make the joint as tight as possible. Grab one adapter with each wrench and turn the two wrenches in opposite directions. It is important that a generous amount of silicon gets squeezed out between the adapters by the force of tightening, as this makes the joint waterproof.

Repeat this process for the other five male adapters to female adapter joints. By the end of this step all three barrels will be joined together by waterproof connector pipes.

Let the silicon dry for 24 hours before moving on to the next step.

STEP 11. Assembling the up-pipes.

Cut a 20" long piece and two 3" long pieces of 2" pipe for the plant tank.

Cut another set (one 20" piece, two 3" pieces) for the fish tank. Use tee fittings to install them into two of the barrels as shown the diagram. Because the fittings and pipe are inside the tanks, they do not need to be held together with cement or silicon sealant.

Remember that the water has to enter a tank at the top, flow to the bottom, and then go up an up-pipe to exit that tank and enter the next. Therefore, It is important that you arrange the up-pipes correctly. When set up correctly, only one up-pipe should be attached to each connector pipe assembly.

 

STEP 12. Assembling the filter pipe.

Cut two 3" long pieces of 2" pipe. Install these into the third, empty barrel. Now carefully measure and cut an up-pipe of 2" pipe for the filter tank. It is important that the intake lies flat on the bottom, so carefully measure the distance between the tee fitting at the top and the el fitting at the bottom. Using three more el fittings, cut short pieces of 2" Pipe to make the intake pipe as shown. You may need to trim these pipes to make them fit.

Once you have figured out how the filter assembly will fit, disassemble it and perforate the pipe by drilling º" holes approximately 1" apart over the entire surface of the intake. This will allow water to enter the up-pipe without compromising the strength of the pipe. Reassemble the perforated pipe and install into the filter tank.

STEP 13. Final positioning.

Before- you put anything heavy into the tanks (like water or rocks) you should make sure that the tank is properly positioned. The plant tank should be in the sunniest spot. The entire system should be level. If you don't have a level, you can use a bowl full of water on a long straight board instead. If you are placing the system on gravel or on loose soil, you should position the whole system on top of a 4'by 4' piece of plywood or a large, sturdy pallet. This will prevent the system from settling unevenly

STEP 14. Filling the filter tank.

If you are building this system inside a budding, you should consider how heavy it will be and whether the floor will support it. The floors of most modern buildings will easily hold the weight of this system. If your building is old, and you are unsure about the strength of your floor, you should consult a professional engineer. They will be able to tell you if your floor can support a weight of 150 to 200 pounds per square foot.

Carefully fill the filter tank with the cleaned fill. "Cleaned fill" means things like crushed brick, rock pieces, large gravel, or other rock-like materials that are free of broken glass, metals, and other contaminants. Be sure to carefully rinse off any dust or mud, as this will cloud the water.

Place the fill piece by piece into the filter tank. You should try to put larger pieces in the bottom, adding medium and pieces as you get near the top.

When filling around the filter pipe, try to place the fill so that 'it doesn't rest directly on the pipe.

When the filter tank is three-quarters full, lay the sheet of burlap or filter cloth over the fill. The rest of the tank should be filled with calcium carbonate materials such as shells or dolomite chips.

STEP 15. Rinsing and leaching the system.

Fill the system with water from a hose. If the fill is dirty, then it will cloud the water with sediment. You may need to fill and drain the tanks several times in order to clear the water. When the water appears fairly clean, fill the system and let it leach for 24 hours. Drain the tanks and fill them again.

STEP 16. Inoculation.

Inoculate the tanks with biological materials. Sprinkle the compost and soils onto the top of the filter tank. Add the pond/stream/river water to in the other two tanks. Sprinkle snails into all three tanks. Two or three tablespoons of rotten milk can be added to the filter tank to encourage a healthy microbial community.

There are several places where aquatic plants can be added to your system. Emergent plants, such as watercress, can be planted directly into the filter tank. Floating plants, like water hyacinth, can be put on the top of e fish tank or the plant tank. If your plant tank is fairly translucent, submerged plants can be planted on the bottom of the plant tank, but try not to block the up-pipe intake.

STEP 17. Installing the airlift pump.

Attach an air stone to a five-foot long piece of air tubing. Lower the air stone into the up-pipe of the fish tank, almost to the bottom of the pipe. Plug the other end of the air tubing into the air pump and Plug it in. Push it down as far as it will go without causing any bubbles to escape from the bottom of the pipe. You should see water moving as the air water mixture rises in the pipe and is forced into the next barrel.

The airlift is all that is required to circulate water in this system. The system works best when the water level half fills the connector pipes, so adjust the water level by adding or removing some water.

The other air stone and tubing should be suspended 'in the fish tank. This provides oxygen to the fish. You will have to weigh it down with a brick or rock. Remember to place the air pump above the system in order to prevent it from being flooded.

STEP 18. Preparing the system for fish.

You should let the system run without fish for a few days, so the various micro-organisms have time to stabilize. This also allows any chlorine that may be present in the water to be released into the atmosphere.

Chlorine is found in tap water and is toxic to most fish, so you should let tap water sit for 24 hours before using in any case.

Before introducing any fish, block off the entrance and exit of the fish tank with '/4" mesh or smaller to prevent them from escaping into the filter or plant tank. The mesh can be held on by elastic bands for easy cleaning.

If you are planning on keeping fish that require high temperatures (e.g. Tilapia), you will have to install a submersible heater 'in the system or put the system in a hot place such as a heated greenhouse. Because the system contains a lot of water, it will take a day or two for the water to warm up to the desired temperature.

STEP 19. Adding the fish.

You have to introduce the fish slowly to prevent them from being too stressed. If the fish came in a bag, open the top to allow oxygen to enter. Float the bag in the fish tank for an hour or so to allow the water inside the bag to come to the same temperature as the tank. You can hang the open bag from the tee fitting so that the fish don't swim out. Once the temperature is the same, add a little bit of water from the fish tank into the bag. Five minutes later, add a little bit more. Do this a few more times, then slowly tilt the bag underwater so that the fish can swim out of the bag and into the tank.

STEP 20. The first few days.

It is a good idea to cover the tank after first introducing the fish because sometimes fish will try to escape from a new tank. After a few days, the fish will become accustomed to their new tank and a cover will no longer be necessary.

When fish are first moved, they may not be as hungry due to stress. Feed them only a little bit at first, gradually increasing the amount of food as they become accustomed to their new environment.

If all your fish die in the first few days, then something is wrong with your system, with the fish, or something happened during transit. Call the person you got- your fish from and try to figure out what the problem could be. Usually, you can get replacement fish at a discount if you can convince the fish supplier that there was something wrong at their end.

MAINTENANCE

 

Regular maintenance helps keep a system healthy by spotting small problems before they become big problems. The regular tasks that you need to perform are listed according to how frequently they need to be done.

Daily Tasks

1. Feed the fish. You can feed fish until they stop eating, or feed them a set amount. Calculating the exact amount of feed to provide is quite complicated, so I suggest feeding them until they stop eating on a daily basis. It is important to watch your fish eat. If they aren't eating happily then there may be something wrong.

2. Check that the water level half fills the connector pipes and add water if necessary.

3. Check to make sure screens over the inlets and outlets aren't clogged.

4. Check the air stone to make sure that it isn't clogged and that the air pump is functioning properly. Clean or replace the air stone when appropriate.

5. Look at the fish to see if they seem healthy.

Weekly Tasks

1. Harvest excess plant materials feed to fish or put into compost.

2. Check sediment levels at the bottom of the fish tank. They should not be building up but rather be removed by the airlift pump. If they have built up, use a siphon to remove any excess.

3. Check ammonia levels. There are numerous kits to measure ammonia available at aquarium stores - read the directions carefully. If ammonia levels are too high, cut back on feed and/or increase aeration (i.e. add another air stone to the fish tank.) .

Monthly Tasks

1. Harvest and restock fish, if required.

2. Remove 10 or 15 gallons of water from the system and replace with water that has sat overnight to let chlorine escape. Chlorine is present in all tap water and can kill or harm fish. By letting it sit in a bucket overnight, most of the chlorine will escape into the atmosphere as gas. It is a good idea to always let water that you Intend to use with fish sit overnight.

Use any water that you remove from the system in a garden. It is an excellent liquid fertilizer.

Yearly Tasks

1. Remove oyster shell/dolomite layer and rinse. Remove the filter cloth and rinse out any clogged sediment.

 

CONCLUSION

 

You are now the proud owner of a recirculating aquaculture system with live, happy fish in it. Congratulations! You should read the Maintenance chapter to find out what you should be doing to keep your fish and your system alive, growing and happy.

The Urban Aquaculture ManualTable of Contents • Chapter 1 • Chapter 2 • Chapter 3 • Chapter

4

webofcreation@lstc.edu

 

The Urban Aquaculture Manual

by Jonathan Woods

Sponsored by Heifer Project Internationalwith assistance from the Evangelical Lutheran Church of America

 

 

 

Chapter Three

 

An Aquaponic System

INTRODUCTION

 

Aquaponics is the combination of aquaculture and hydroponics. While algae, submerged plants, and floating plants do a good job of removing fish wastes from a recirculating aquaculture system, so can lettuce, basil, or many other common vegetables and herbs. Fish wastes can be treated with a biofilter and then allowed to pass through hydroponic troughs,

where the roots of cultivated plants can remove the wastes as fertilizer.

In this system, fish are fed in the fish tank. Their wastes are pumped with an airlift pump into a biofilter pipe. This pipe is a smaller version of the biofilter tank used in the recirculating system. As waste-filled water seeps through the biofilter pipe, bacteria and other micro- organisms breakdown and convert the wastes into forms that plants can use as fertilizer.

At the end of the biofilter pipe, the water spills out through an irrigation bar which distributes the fertilizer- filled water into the two hydroponic troughs. As the water slowly flows along the bottom of the hydroponic troughs, plants in pots draw water and nutrients from the passing flow.

Small plants and seedlings are watered through the wicking action of wicking materials in the bottom of their pots. Larger plants grow roots out of the bottom of their pots and into tile flow, soaking tip lots of water and fertilizer.

After passing through the biofilter pipe and the hydroponic troughs, the cleaned water trickles back into the fish tank, where the cycle starts once again.

This chapter shows you how to build a simple aquaponic system that will produce both fish and vegetables. Like the simple recirculating system in chapter two, it runs off of one double-outlet air pump. This design takes up a four foot by nine foot space but can be made smaller if space is limited.

SITE

This system needs more light than the simple recirculating system, because vegetable crops tend to need more light than water plants. A greenhouse, bright south-facing window, or protected outdoor location is best.

If, you want to put it inside, you'll need to use lights to grow your plants.

 This system weighs less than the simple recirculating system, but you should get an engineer to look at any floor you think may not be strong enough. There are no through-hull fittings in this system, and as long as the hydroponic tray is higher than the fish tank it can be put just about anywhere. For example, you could put the hydroponic tray on top of an old table with the fish tank on the floor at one end.

PARTS AND TOOLS NEEDED

Hardware

1- 50 gallon plastic barrel - preferably food grade and semi-transparent

1 - 10' long 1/2" PVC pipe

1 - 1/2" PVC male adapter

2 - 1/2" PVC tee fittings

1 - 10' long 4" PVC pipe

1 - 4" end cap

 

1 - 4" "L" fitting

1 - aquarium air pump with double outlet

2 - air stones

10' of air stone tubing

1 - 4' x 8' board, 1/4" or thicker

3 - 1" x 4" boards, 8' long

2 - 1 " x 2" boards, 8' long

50 - 1" nails

White or carpenter's glue for bonding the boards together

1 - 6' by 10' piece of polyethylene vapor barrier (6mil is best). This is simply a thick plastic sheet used to protect houses from moisture and can be found in most hardware stores.

Staples for staple gun (if using)

5 gallons of oyster shells or dolomite

Plastic pots for plants

Bag of potting soil

Bag of perlite, vermiculite, cocofiber, or peat moss

 

Tools

Saw - to remove tops of barrels, cut boards and cut pipe

Hammer

Staple gun (optional - see STEP 9)

Felt pen - to mark cuts

Power drill

3/4" hole saw (or large bore drill bit)

Scissors - to cut plastic

 

Biological Materials

Buckets of water from local lakes, rivers or ponds

A handful of fresh compost

A handful of good garden soil

A handful of soil from a forest

A handful of soil from a meadow

Some snails from an aquarium store or local pond

Vegetable and herb seeds and seedlings

20 - 30 fish fingerlings (Nile tilapia are recommended)

 

CONSTRUCTION PROCEDURE

This system takes a day to build if you can get all the materials together and wash and leach the barrels beforehand.

It is a good idea to add the plants a week or so before adding the fish, so that their roots can grow into the water. Add the fish after the system has stabilized for a week or two. Be sure to read ALL the Instructions CAREFULLY before starting to build so that you won't be surprised by what comes next.

STEP 1. Rinsing the barrel.

Rinse out the barrel with a garden hose. Barrels often contain nasty toxins and should always be handled with care. Wear gloves, long sleeved shirts, long pants, and safety glasses when rinsing.

STEP 2. Leaching the barrel.

The barrel can be leached by filling with water, letting it sit overnight, and then draining the next day. Do this several times, using hot water if available. This will draw out any toxins that are in the plastic itself.

STEP 3. Cutting the lid out of the barrel.

Cut the lid out of the barrel as shown. Leave the rim intact, as it provides support for the barrel, and be sure to leave a small flap to hold the airlift pump. There are several ways of cutting the lid out, depending on what tools you have available. For example, you could drill a small hole and then use a skill saw, or you can drill holes all the way around if you don't have a saw.

STEP 4. Washing the barrel.

Wash the barrel. Use soap, warm water, and a scrub brush or sponge. Or take the barrel to a commercial car wash. Rinse off the soap, re-fill, and let the barrel leach overnight again.

STEP 5. Making the hydroponic trough.

The hydroponic trough is basically a box lined with plastic. A plan for a four by eight-foot double trough is  shown. You can make the trough longer, shorter, narrower, or wider, if you wish. The important thing is that the drains are spaced so that they drain directly into the fish tank, and that there is a space to hold the biofilter pipe.

Cut one of the 1'x4" boards into a 46 1/2 " piece and two 16" pieces. Glue and nail the other two 8' long 1" x 4" boards onto the long sides of the 4' x 8' board. Glue and nail the 461/2" piece onto one end of the 4' x 8' board, and glue and nail the 16" pieces to the other end as shown.

Find the center of the 4' x 8' board at-id mark it with a pencil. Mark a line 2 1/4" from the center line on both sides of the center line. Glue and nail the two 1 x 2" boards so that their inside edge runs along the 2 1/4" lines. You should end up with a 4 1/2-" wide trench in between the two 1" x 2" boards, where the biofilter pipe will sit.

Using sandpaper, go over the inside of your trough carefully, looking for sharp edges and splinters that might poke through the plastic. Also look to see if any nails have come through that might tear the plastic.

The Urban Aquaculture ManualTable of Contents • Chapter 1 • Chapter 2 • Chapter 3 •

Chapter 4

webofcreation@lstc.edu

 

The Urban Aquaculture Manual

by Jonathan Woods

Sponsored by Heifer Project Internationalwith assistance from the Evangelical Lutheran Church of America

 

Chapter 4

Resources

 

INTRODUCTION

 

This chapter contains information that should be useful in running your system. The information is arranged according to topic, and each section starts with background material relevant to the tables and lists in that section.

 

FISH FOODS

 

Some fish are fussy eaters; most fish will eat a wide range of foods, while a few will try just about anything. Garbage in, garbage out is as true for fish as for humans, but determining exactly what is garbage for a fish is slightly more difficult than human nutrition. Fish grow faster when there is a lot of protein in their diet, although they need their carbohydrates and vitamins as well. A good food to start with (and an excellent back-up food in any case) is any sort of cheap dog food or trout/catfish chow if you can get it. Another good all around food for fish is seaweed or kelp meal. This is especially good for baby fish and can be purchased at garden centers or feed mills.

 

Feeding ideas

 

1. Fertilization. If you are raising a herbivorous fish, or if the fish you are raisin cats something that grows readily in your system then fertilizing the tank to promote algal (and therefore zooplankton) growth. Compost is probably the best

sort of fertilizer for a small system. Use only a handful or two and then wait to see what happens.

 

2. Food scraps. There are a lot of wasted foods out there, and if you can get your hands on a steady, local supply, you could end up feeding your fish for free. Tilapia will cat vegetable peelings, as will carp. Many fish will take meat scraps, fishmeal, or leftovers from the table. There are recipes available for homemade fish feeds from waste materials - see the book Freshwater Aquaculture for a good introduction. Here are some suggestions of food resources in the city.

Stale bread and bakery throwouts

Fish scraps - frozen and ground

Meat scraps - fresh or frozen and ground

Vegetable peelings

Old vegetables from markets

Restaurant wet wastes

 

These can be found at numerous commercial businesses, as well as public places like schools and institutions. If your fish will cat it, you probably produce enough food scraps 'in your house to feed a healthy population of tilapia. If you do not have a dog, then a tank full of leftover-eating fish can be your substitute.

 

3. Collect invertebrates for food. Most fish love eating insects, especially live ones, - and if you know where to look and are not too squeamish, there are lots of potential insect sources in and around a city. The first one that comes to my mind is cockroaches squish 'em and toss them to the sharks! Many of these can be trapped and (for the intrepid) can even be cultured right in your own backyard. Here are some ideas.

Earthworms

Cockroaches

Crickets

Snails

Slugs

Flies

Moths

Beetles

Buried beetle and wasp larvae

Big, juicy caterpillars

4. Keep a worm bin. Red wigglers are a favorite food of tilapia and also help you reduce your household wet wastes into nice, indoor compost. God's Gang, who have several aquacultural ecosystems set up in Chicago, grows red

wigglers both for sale and to feed to their fish. Fish fed with earthworms on a regular basis grow healthy and strong due to the high vitamin content of these little guys.

5. Grow some plants. Fish, especially herbivorous fish, will eat a lot of plant materials that we do not even consider to be food, Of course, fish will eat just about all the fruits and vegetables that we eat, so these are not listed here but are also good sources of food. The following list shows some of the more exotic parts of the fish diet.

Water hyacinth - fish will not eat it unless you take it out of the tank, chop it up, and then return it to the tank

Azolla

Duckweed

Carrot tops

Marigolds

Taro leaves

Purslane

Green tomatoes

Much has been written on feeding fish and the references in the bibliography should give you some direction if you are interested in developing new ways of feeding them. Fish will eat so many things that it is always worth trying something new The best way to test a new food is to put a little bit in the tank and watch for awhile. Usually fish will mouth the new food and then spit it out - it is their way of testing. If they do not eat it right away, leave them alone for an hour or so and check again. The food will most likely be gone by then if they are going to eat it at all. An exception is live foods. Fish seem to know that a live insect or worm will stay fresh until they eat it (or until it dies), so they often let it live in the tank for a few days before consuming it. This is especially true with worms, who can live underwater if the water is well oxygenated. Just as they think that they have escaped, the fish usually eats them!

FISH SPECIES FOR AQUACULTURAL ECOSYSTEMS

 

I am not an expert in raising many different types of fish, but there are so many experts out there already that you can easily find information about the fish you might want to raise. Table 7-1 lists several fish species, their temperature ranges, and whether or not they are easy to raise. The last category was determined from a literature review generally aquaculture authors agree about which species are easy and which are temperamental. It is interesting to note that many widely farmed fish are actually quite difficult to raise. The reason that they are widely farmed usually has nothing to do with how easy or hard they are to raise, but rather how much money they can make for the farmer, and that is why trout and channel catfish are so popular among North American farmers. In countries where people raise fish for their own or local consumption, carp, Chinese carp, and tilapia are much more widely raised.

 

Good places to go for advice about fish are extension agents, pet stores, fish dealers, and the library. Anybody who sells you fingerlings must know a thing or two about how to raise fish, so make sure that some advice is included in the purchase price. Take advice with a lot of salt, however. I cannot remember how many people have told me that I was raising fish the wrong way! Usually commercial fish farmers have little knowledge about recirculating systems but they still know a lot about the particular species of fish that they raise.

 

 

OTHER EDIBLE ANIMALS

 

There are several other species of animal, mostly invertebrate, that you might want to try raising as you become proficient. Most of these are crustaceans, but if you like to eat frogs, why not? All these species are freshwater types and would be suitable for aquacultural ecosystems, providing you do a little background research on their natural

history-

Freshwater shrimp (Macrobrachium spp.)

Crayfish (Procambarus spp.)

Bullfrog (Rana catesbeiana)

Freshwater clams

Turtles

Yabbles (an Australian crayfish)

Giant snail (Achanita spp.)

Escargot (Helix spp.)

Freshwater crab (Halicarcinus spp.)

 

VEGETABLES

 

These are lists of vegetables (including herbs and annual fruits) that grow well under certain conditions or are tolerant of aquatic conditions. Some of the uncommon ones may be difficult to get a hold of in North America but are included here, as you should be able to find them if you look hard enough. Also, some root vegetables have been largely overlooked as they are difficult (or at least impractical) to grow in aquacultural ecosystems.

 

Vegetables that float on the water surface

Water hyacinth

Water mimosa

Watercress

Vegetables that grow in underwater soil (emergent vegetables)

Water chestnut

Lotus

Taro (Colocasla esculentes)

Kangkong (Ipormea aquatica)

Watercress

Indian water chestnut

Arrowhead

Chinese arrowhead

Wild rice

Duck potato

Water celery

Manchurian wild rice

Vegetables that grow well in hydroponics

These are the basic ones. Almost all-common annual vegetables can be grown hydroponically with the exception of some root vegetables such as potatoes. See a good magazine like The Growing Edge or look in the bibliography for books about hydroponics.

Basil eggplant

Mint kale

Arugula lettuce

Chives mustard greens

Coriander peas

Ginger peppers

Parsley radish

Beans rapini

Bok choy spinach

Broccoli sweet potato

Cabbage tomato

Chard zucchini

Chinese cabbage cucumber

Corn

 

AQUATIC PLANTS

 

There are many aquatic plants available both in a good garden center as well as in the local pond. Increasing the diversity of aquatic plants in your system will also increase the diversity of the microorganisms that use aquatic plants as habitat. Many of them can be quite beautiful, especially if the conditions are right for them to flower. Also see the vegetable section for plants in these categories.

Floating plants

Water hyacinth

Water lettuce

Duck-weed

Salvinia

Azolla

Indonesian water hyacinth bladderwort

 

Submerged plants

Hydrilla

Elodea

 

Plants that are rooted in underwater soil (emergent plants)

Cattail

Alligatorweed

Pickerel weed

Smartweed

Lotus

Water lily

Water buttercup

Watercress

 

TROUBLESHOOTING

 

If you maintain a healthy system and do riot overload it with organisms, you should not encounter any serious problems. Every, system is different and therefore each system will experience problems in a different way.

What I have tried to do here is to set up a problem-solving helper based on my experience of what some of the common problems are. If you come to the end of this helper and the problem is not solved then it is up to you - be resourceful!

 

To use this helper, simply look down the list of problems until you find one that sounds like what you are experiencing. There are numbers for solutions listed below. Sometimes a major problem (like Fish almost Dead) will refer you to a lesser problem (such as Pump is Broken) as problems seem to set themselves up in a hierarchy. Check each of these possible solutions in order to see I if they solve your problem. Good luck!

 

PROBLEMS

 

System problems

(P1) - Water is not circulating / no bubbles. (S1) (S2) (S3) (S4) (S5) (S6)

(P2) - Puddles on the floor around the system. (S7) (S15) (P4)

(P3) - Big puddle surrounding the system. (S8) (P9) (S15) (S17)

(P4) - Found a leak! (S9) (S15)

(P5) - Funny smell - rotten eggs. (S10)

(P6) - Funny smell - like manure. (S11)

(P7) - Funny smell - fishy smelling. (S12) (P11)

(P8) - Funny smell - ammonia! (S13) (S12)

(P9) - Cracks in the ceiling in room below system. (S14)

 

Fish problems

 

(P10) - ALL THE FISH ARE DEAD THIS MORNING! (P1) (P5) (P6) (P7) (P8) (S16) (S17)

(P11) - One of the fish is dead, others appear fine. (S18)

(P12) - Fish gasping at surface. (P5) (P6) (P7) (P8) (S19)

(P13) - One fish is swimming funny, covered with lesions, or does not feed with the rest. (S18)

(P14) - Fish attacking each other. (S22) (S23) (S24) (S16) (P5) (P6) (P7) (P8)

(P15)- Some fish seem to be missing. (S7) (S17) (S6) (S25)

(P16)- One fish grows really fast, smaller fish missing. (S26) (S25) (S6)

(P17) - Fish do not seem to grow (SI6) (S27)

(P18) - Fish never get very big, more and more appearing. (S27) (S24) (S16) (S28)

(P20)- Fish are not feeding. (S27) (P1)

 

Plant problems

(P21) - Plants appear unhealthy. (S30) (S31) (S32) (S33) (P26)

(P22) - Plants do not grow. (S31) (P21)

(P23) - Plants grow but are spindly. (S31) (P21)

(P24) - Plants grow well, but no flowers or fruits. (S30) (S31)

(P25) - Flowers appear, but no fruits. (S35) (S31)

(P26) - Insects, insects, everywhere! (S34)

 

SOLUTIONS

 

(S1) - Screens are clogged. These need regular maintenance for smooth operation. Scrub with a brush to remove accumulated algae and debris. If possible, use a larger mesh size.

 

(S2) - Air pump broken or not plugged in. Check for air from the outlet tube. If there is none then you may have blown a gasket. Buy a replacement gasket (US $2-3) at a pet store.

 

(S3) - Air tubing is clogged. Remove the air stone and try to blow through the tubing with your mouth - you should be able to do this easily and feel air coming out the other end.

 

(S4) - Air stone clogged. Air stones get clogged eventually with algae and other stuff They can be cleaned somewhat by soaking 'in vinegar, but will never bubble as well as a new one. Clean or replace.

 

(S5) - There is a clog in the plumbing. Visually inspect all plumbing, use a stick to probe the depths. Sometimes, a fish gets caught in the plumbing and blocks it up. Snails will sometimes congregate in plumbing to the extent where water flow is blocked. Exclude both with some 1/4" mesh. (S6)

 

(S6) - There is a clog in the b1ofilter. If you make your biofilter too fine, or you do not use a large enough uptake pipe, you may find that your system clogs. Also, your biofilter may need a good cleaning. Set aside a few hours and take apart your b1ofiltcr to find out what the problem is. (S25)

 

(S7) - Fish like to play. Sometimes newly introduced fish splash around while they settle into their new environment. Sometimes they jump to their death. Put a net over the fish tank to prevent jumpers.

 

(S8) - There is a big leak in your system and you had better find it soon. Rescue what you can and try to determine if the leak is repairable. Usually a leak is found at a joint or in the biofilter - check those first.

 

(S9) - If you can, drain the System to below the level of the leak, let it dry out, and then repair with silicon. It is almost impossible to properly repair a leak while it is wet. Alternate layers of plastic bags and duct tape may do the trick, temporarily.

 

(S10) - Toxic hydrogen sulfide is being released! Act fast; provide as much dissolved oxygen as you can to the afflicted tank. Gently vacuum up any anaerobically decomposing material from the bottom of the tank. (P1)

 

(S11) Methane is being produced. Eventually, this can cause problems, especially if other people have to around your system. Gently vacuum up any anaerobically decomposing material from the bottom of the tank. (P1)

 

(S12) - Food is rotting in the system. Locate and remove any obviously rotting pieces of food. Avoid feeding too much.

 

(S13) - Ammonia is highly toxic, aerate immediately Prevent future problems by encouraging nitrifying bacteria in a biofilter. (P1)

 

(S14) Call an engineer. Your system is too heavy for the building structure -move it to the basement.

 

(S15) - Leaking water can cause rotting problems with wooden structures. Protect the floor with plastic or move the system.

 (S16) - Check the water temperature and compare it with recommended ranges for your fish.

(S17) Fish tanks in semi-public places are prone to vandalism. Respond appropriately.

(S18) - Remove fish and inspect for signs of disease or attack. Suspicious spots, missing scales, funny colored eyes, and other symptoms all could indicate a diseased fish. Alive still - S (20). Dead - S (21).

(S19) - Dissolved oxygen is in short supply. Aerate immediately by whatever means necessary. (P1)

(S20) - Keep fish isolated in a well-aerated tank. Feed only sparingly and only if fish seems willing to eat. (S21)

(S21) - Increase aeration and keep a close eye on the rest of the fish. Consult a fish disease handbook and do a biopsy if you feel up to it.

(S22) - The attacked fish may be ill. See (S18).

(S23) - The attacking fish may be ill. See (S 18).

(S24) - The fish may be breeding. Consult natural history information about that species in order to confirm this.

(S25) - Sometimes fish escape into other parts of the system. If they have you will find them eventually.

(S26) - Fish are eating each other. Either come to terms with this horrible fact of life, or choose a less cannibalistic species. Increasing the availability of live food and reducing population density will reduce cannibalism. You could also try removing all the big fish, or removing all the small fish (called "grading").

(S27)- There may be a problem with the foods you are giving them. Try something different for awhile to see if they improve.

(S28)- Fish may be overcrowded. Increase water circulation and biofiltration or reduce fish density.

(S30)- There is a nutrient deficiency. Check a nutrient table to see if one of these matches the symptoms. Nutrient tables can be found in good gardening books.

(S31)- There is not enough light. Move the plants to a place where they can get more light, supplement the available light, or grow more shade-tolerant plants.

(S32)- The plants are diseased. Check a plant disease book. Remove and destroy diseased plants.

(S33)- The roots are waterlogged and possible rotting. Evaluate your growing system and consult the hydroponics literature.

(S34)- The plants may be infested with detrimental insects. Confirm with an insect guidebook. Feed infested plants (insects included) to the fish. Look in a good organic gardening book for ideas about controlling future infestations.

 

(S35) There are no pollinators. Open the window or, if it is too cold, investigate artificial pollination techniques.

 

BIBLIOGRAPHY

Books and Manuals

I have in my opinions on the following books, which I have found useful for understanding and learning about aquaculture, hydroponics, and agriculture in general. Usually, the most interesting materials are in magazines and journals, but there is a lot of historical, reference, and background material in larger books. Older books tend to be interesting and informative - often they contain ideas that were rejected for one or another reason by the rather narrowly focused aquaculture/hydroponic industry. Much early work on sustainable and organic methods in these fields was rejected outright or modified by the industry to conform to sterile, chemical agriculture. Now, as sustainable aquaculture and organic hydroponics arc coming into vogue, many of the best books are out of print. A good public library can be a gold mine of useful information from the past.

 

Chakroff, Marilyn. 1976. Fresh water fish pond culture and management. Volunteers in Technical Assistance (VITA) publication #36E

 

- The Peace Corps classic. Chakroff wrote this manual from firsthand experiences while serving in the Philippines with the Peace Corps. While there is little information about tanks, the information about fish, their biology, and how to take care of them is accurate and accessible. Most libraries seem to have a copy - worth the effort and expense to photocopy this book if you can find it.

 

Mollison, Bill. 1997. Permaculture -A Designer's Manual Ten-speed Press.

Mollison, Bill. 1998. Introduction to Permaculture. Ten-speed Press.

 

- Bill is one of the most creative agricultural thinkers of this century. All of his works 'include sections on aquaculture and the underlying philosophy of permaculture is both interesting and useful for anyone who likes to contemplate our place in the world. Full of new ideas and practical advice.

 

McLarney, William. 1998. Fresh water aquaculture. Hartley & Marks, Port Roberts, WA.

 

- The standard textbook on small-scale, freshwater aquaculture, McClarney was a founding member of the New Alchemy Institute and worked with John Todd 'in his early career. This book was out of print for a long time but the 1984 edition has now been reprinted and it is available through special order. Lots of information and charts, but a lot of the contact information is out of date and useless. He tries to promote using North American species for aquaculture as opposed to introduced species like carp. I would not recommend purchasing this book unless you want to raise N. American species, want more technical information about aquaculture, or are interested in other forms (such as ponds, lakes, cages, etc.)

 

Logsdon, G. 1978. Getting food from water. Rodale Press, Emmaus, PA

An excellent but out of print book. Seems that all the alternative agriculture organizations were running interesting programs on aquaculture and aquaponics in the seventies. Now Rodale publishes magazines like "Men's Health" and the New Alchemy Institute is defunct. This book is an excellent alternative to McClarney's text. It Is written in a more accessible style and seems to be more on the scale of home gardeners. There's even an account of an old man who raises catfish in a bathtub. Out of print but a valuable read if you can find it.

 

Todd, Nancy Jack and John Todd. 1994. From Eco-cities to Living machines: Principles of ecological design. North Atlantic Books.

John Todd and his wife outline their philosophies and ideas about ecological engineering and the role of ecology in design. Not a very handsome book, but it does have some interesting ideas about aquaculture, cities, and the future of the planet. Generally, while the ideas coming out if the New Alchemy Institute are pretty cool, the books and other publications from the members of this group are sort of vague and disappointing. If this group wants the world to change using its ideas, then they need to write a detailed manual about building living machines. There are a lot of willing people out there who are sort of puttering in the dark trying to do good things but apparently missing key details.

 

DeKorne, James B. 1992. The hydroponic hot house: low-cost, high-yield greenhouse gardening. Loompanics Unlimited.

 

DeKorne is the last of the paranoid survivalists, but has developed some very useful systems for growing things hydroponically indoors. He is an inventor who has limited resources - the results are accessible, cheap, and easy to build systems.

 

Resh, Howard Al. 1 990. Hydroponic home food gardens. Woodbridge Press.

 

Resh is the dean of commercial hydroponics in North America. Every good hydroponics store will be stocked with his books, and libraries usually have a few copies. This book is the most accessible of his works, and although the ideas are fairly narrow-minded and conventional, at least it provides a solid survey of the hydroponic industry in general.

 

Douglas, James Sholto. 1985. Advanced guide to hydroponics (soilless culture).

 

Douglas, James Sholto. 1976. Hydroponics: the Bengal system.

 

- Douglas was one of the first writers about the 'new' science of hydroponics and he was very keen on organic and sustainable methods of production. If you can find any of his books, snap them up. Reading Douglas after reading Resh, you realize that Resh's entire scope would fit into a specialist chapter or two of Douglas' global perspective. Look for these books in the library.

 

Addey, William and Karen Loveland. 1998. Dynamic Aquaria. Academic Press.

A fantastic book about how aquariums and ecosystems work, written by two biologists. Full of explanations about how different environmental factors can influence fish and other organisms. Also has good ideas about

how to stock an aquatic system with plants, fish, and other organisms.

 

Magazines

 

Of all the magazines published currently, the Growing Edge is by far the most relevant and useful. It often has article about aquaponics and organic methods, and is an excellent source for latest hydroponic ideas. Practical Hydroponics and Greenhouses from Australia is equivalent to the Growing Edge in quality and outlook, but can be expensive because it is imported. The out of print Journal of the New Alchemist and the New Alchemy Quarterly have good articles about living machines but are rather difficult to find.

A good all-around gardening magazines is Organic Gardening. It is widely available and contains useful information about vegetables, composting, and the occasional water-gardening/hydroponic/aquaculture article. Older issues are better than recent issues, as the current editor seems more concerned about growing ornamentals than food.

Aquaculture Magazine the best source for industry news and format. Their articles are well written and researched, although keep in mind that the bottom-line is the driving force behind this magazine. Their annual Buyer's Guide is a must-have. It tells you where to get everything you could possibly need for aquaculture, especially sources of fingerlings.

All of these magazines have extremely useful back-issues. You can find these in a good library system or you can often buy them at a discount form the publisher.

Aquaculture Magazine

P.O. Box 2329

Asheville, NC, 28802

USA

www.aquaculturemag.com

 

The Growing Edge Magazine

1-800-888-6785

www.growingedge.com

 

Organic Gardening

Rodale Press

Emmaus, PA, 18049

USA

www.organicgardening.com

 

Practical Hydroponics and Greenhouses

P.O. Box 225

Narrabeen, NSW

2101 Australia

www.hydroponics.net.au

 

Journal of the New Alchemists, New Alchemy Quarterly - Both are out of print. Try contacting Ocean Arks International or your local public library to locate back issues.

Free Literature

Generally, your local extension agent will be able to provide you with information about some aspects of your proposed project. Here is one agency that has been particularly helpful.

Southern Regional Aquaculture Center

c/o Michael P. Masser

106A Swinger Hall

Auburn University, AL, 36849-5628

USA

(334) 844-9312

(334) 844-9208 (fax)

mmasser@acesg.auburn.edu

 

This center has put a lot of effort into promoting aquaculture. They have an excellent range of free publications, many of which are highly useful for recirculating aquaculture enthusiasts. They are one of the few places which promote crayfish, Chinese carps, tilapia, and exotic shrimps in the USDA system. They are also excellent sources of information about where to buy less common species. Ask for the following pamphlets in particular.

SRAC282 Tank culture of Tilapia

SRAC451 Recirculating aquaculture tank production systems. An overview of critical considerations.

SRAC 452 Recirculating aquaculture tank production systems. Management of recirculating systems.

SRAC 453 Recirculating aquaculture tank production Systems. Component Options

SRAC 454 Recirculating aquaculture tank production systems. Integrating fish and plant culture.

Herb, Frances Raising snails for food

WEB SITES

 

Web access is becoming more widely available, and even In the developing world Internet is available at reasonable prices (approx. US$5 per hour) in Internet cafes. There are tons of resources on the Internet but beware anybody can write Just about anything in cyberspace and nobody checks their work. Be wise about advice and ideas that you glean off the Internet - if It sounds too good to be true, it probably is.

 

The following sites have useful information and will lead you to other sites.

www.jeffcook.com/hbpond.htm1

Jeff's half -whiskey-barrel page, while not quite as funny as Eric's is also full of information. He has a lot of different opinions from Eric, but the two end up with the same thing in the end. Jeff 's links are extensive.

www.livingmachines.com

The Living Technologies company site. This site is John Todd's consulting site. There are some interesting photos, information, and links, as well as examples of how Todd has applied living machines to industrial problems.

 

ext.msstate.edu/anr/aquaculture

Access to Mississippi State University's excellent collection of aquaculture extension information.

www.kloubec.com

- A major tilapia producer in Iowa, their site gives a good overview of this species.

ag.arizona.edu/azaqua/tilapia

- A large but disorganized site containing lots of information about tilapia.

www.itv.se/rainbow

- Swedish farmers who grow trout and vegetables in a recirculating system,

www.townsqr.com/snsaqua

- Home page of the Sperraneo family who are successful aquaponic farmers in Missouri.

www.cropking.com/store/AquaM/AquaSystem.htm

o A large-scale and high-tech aquaponic system made by a major hydroponic equipment manufacturer.

 keywords to search with for internet information

aquaponics

hydroponics and aquaculture

living and machines

aquaculture and recirculating

alternative and aquaculture