Pond Boss Forums AQUATIC VEGETATION Balance of plants in the environment CATMANDOO Aquaponics Experiment

Early this year we had a Pond Boss gathering at CATMANDOO World Headquarters, complete with the Pond Boss himself, Bob Lusk.

At this gathering, we were introduced to small-scale aquaponics through a friend from West Virginia University. It is a process where fish and plants "grow in harmony together."

In the approximate 8 months since I first learned about this, I've found that it is quite popular with the counter-culture, the drug culture, those who are trying to make food production far more sustainable, and those who just want high-productivity backyard fresh fish and fresh vegetables without chemicals -- in a very limited space, with minimal power requirements, minimal water usage, and minimal environmental impact.

There are multiple great methods for aquaculture. One of the simplest is "barrelponics" where all you need are three plastic barrels. This link provides an entire PDF manual for setting up and maintaining such a system:

Barrelponics Instruction Manual

I was about to setup a barrelponics system,when I was offered two free 300 gallon Intermediate Bulk Containers (IBCs). If you "Google" IBC Aquaponics, you will find more info than you can possibly digest in several days. Interestingly, the IBCs are quite commonly available for free, or at very little cost.

Mine took a little bit (actually a whole lot) of cleaning. But, as of tonight, I've got five bluegill and one small bass living in the bottom portion, and tomorrow I will start lettuce, spinach, beans, and cucumbers in the upper portion.
I'm planning on adding a few 6-8 inch channel catfish tomorrow afternoon. We are hoping to have fresh vegetables for Thanksgiving and Christmas dinner.

I put my system inside a small 6x8 greenhouse that will hopefully stay warm enough until Christmas to provide the vegetables.

Here it is inside my small greenhouse frame, with the tank wrapped in black plastic to keep sunlight from the fish tank, hopefully preventing algae buildup -- and hopefully adding a little solar heating to the water.




The bottom part is home to the fishes, which will get hand fed, based on the water temperature. The top part is filled with about 7-inches of pea-gravel that will become the growing medium for the plants. A simple pump-and-drain system will move water from the fish tank to the grow bed. The growbed will use the nutrients (like ammonia) from the water that has been "fouled" by the fish, and return it as fresh, clean, and aerated water to the fish.



I'll post progress, as it happens.

Very interesting. I will be watching!

Interesting indeed!

Ken, I thought of you as I was cooking dinner last night. Venison steaks, part of a Maitake mushroom (found 3 on Sunday, although one was whacked by frost and soft so I only kept 2) and the last of the greem beans from my sisters garden.

I will be watching this as well, since I hope to try this out next year.

By the way does anyone know what type of Tilapia those are in the manual Ken posted above?

How do you get the solids (poo and other stuff) out of the tank before you spike some parameter that kills your fish?

Just curious.

Winter??? In that unit??? Hmmmmmm....

I am pumping from the bottom of the tank. I don't have my timer on the system yet, but I intend to flood and drain the top every three hours. The biggest issue is getting the ammonia out. But, that is what turns into nitrites/nitrates when I flood and drain -- and that will be taken up by my plants.

As for winter, I will let the system run until we get to a series of days where it does not get above freezing during the day, or the greenhouse gets below freezing and my plants die. My little greenhouse really heats up with just a little bit of sunshine when all the flaps are down. The approximate 250 gallons of water, and the rocks in the top should act as a pretty good moderator of temperature also.

Ken

I have always been under the impression that all living organisms that were specie-specific adapted to a certain amount of sunshine required at least that amount of sunshine to maintain an acceptable level of homeostasis. Your configuration appears to block all sunlight from entering the fish holding container. Will this not eventually cause a negative health effect?

I think it would only cause a negative effect in the summer when the temperature would get extremely hot

The bottom tank actually gets a fair amount of sunlight. Some is direct, but most is indirect. In many of the local commercial fish operations that I am familiar with, the fish are raised indoors, with only fluorescent light, and in general, at far fewer lumens than my water is receiving during daylight hours. From experience, it also seems that fish raised in cage culture prefer to stay under the lids, and not in the open sun.

The photos shown in the post above were taken after dark, but here are a couple from late this afternoon as the sun was about to set. As can be seen, even at dusk, it is still fairly bright.





Yesterday I added five 6-7 inch channel catfish to the five bluegill and the one small bass that I put in a the day before. So far they are not eating. However, the water is only at about 55 degrees F. Tomorrow the greenhouse cover goes over the frame. That should warm the water considerably, as the greenhouse will reach around 100 degrees F, this time of year, during afternoon sun.

This afternoon I planted Alaskan peas, green beans, five kinds of lettuce, spinach, two kinds of cucumbers, and some summer squash. All have harvest days of 50-60 days after sowing. I'm hoping we can have some fresh vegetables for Christmas dinner -- maybe even some for Thanksgiving dinner. Time will tell.

Ken

Early yesterday, a friend helped me put the greenhouse cover on the frame. This was the first time I'd used the greenhouse in the fall. The sun is below the tree line, and the leaves are still on the trees. It will probably be at least two weeks before the greenhouse gets significant sun.

The water tonight was still only at 53 degrees F. One bluegill came to the surface for food.

I built a timer yesterday that allows me to flood and drain the growing area, which also provides aeration to the fish water, eight times per day.

So far, nothing has germinated -- but is has only been two days.

Ken

pretty neat!!

Fascinating stuff, Ken.

Have you thought about the degree of inputs (presumably, electricity for a heater) that it would require to keep the system going throughout the winter?

First things first, of course, but just wondering if you have thought about a six-month operation.

I had wanted to get this thing started back in August, but time just didn't permit that. I'm hoping I can keep it warm enough until Christmas with just the greenhouse. I plan to start it back up again in March.

If it really works, I plan to at least double, and maybe triple the grow bed area. Right now I have about 65 inches of fish in the 250 gallons of water. Most things I've read say that you can maintain an inch of fish per gallon, so I should be able to add a bunch more fish too.

I wouldn't want to try and heat it with anything but solar. I think that would be just too costly. Right now, the only power requirement is for a 25 watt pump that runs for a total of 56 minutes a day (8 times per day for 7 minutes each time).

Ken

Ken you've got an interesting experiment going that I think a lot of people will be interested in, I've been thinking about making a portable structure to cover my little backyard pond in cool weather and grow some veggies in floating islands.

One thing that might help increase light to speed up growing would be putting aluminum foil on walls that don't receive direct sunlight.

Great project.

Ken:

I've been doing some reading on RAS systems. The amount of fish all depends on the amount of filtering area. And, from what I've read, the amount of filtering area is determined more by the amount of food that the fish are fed than by the amount of fish in the system. But, I haven't seen anything written about how the water temp affects the effectiveness of the bacteria in the bio filter. I have a gut feeling that the water temp matters more than people think.

Temperature is critical in many of the processes, both chemical and organic, that take place in an aquatic eco-system. This is especially true of bacteria. Nitrifying bacteria have been reported to function at peak efficiency when temperatures are around 80F. This efficiency drops as temperatures drop until all conversion is ceased at about 34F.
A side note on the amount of food being a main concern. One should also take into account that 85% of the food consumed by fish turns to waste, only 15% is utilized by the fish.
The 1 inch per gallon of water stocking level previously referred to can, I fear, rapidly become problematic unless the filter bed is greatly increased in size and the water turn-over rate is increased proportionately. A turn-over rate of once every 30-60 minutes would seem to be indicated at this dense a stocking level.

Scott and Instar,

I agree with what both of you say. If I go to denser stocking next spring, I'll add more grow beds. When I get time I plan to go to a continuous flood and flush system with bell siphons and a different pump. Right now I'm doing very minimal feeding due to the temperature. I may have to supplement my plant food within the water.

Ken

When I checked my experiment late this afternoon, I found that the lettuce, spinach, and green beans had sprouted.



The water is 62F degrees, top to bottom. The food I've been putting in has been disappearing. Much of it could just be sinking to the bottom, but I know that at least some of it is being eaten by the larger bluegills that I've seen at the top eating it.

The timer I added cost about $16. The pump draws less than 2 amperes at 12 VDC. The pump is on for 56 minutes every 24 hours (8 times per day for 7 minutes each time). That puts me at about 2 ampere-hours per day of consumption. When spring comes, I think I'll make the whole thing solar just to prove to myself that it can be done completely without external energy sources.

Here in my little timer mounted in a weather-resistant housing:


And, here is the little greenhouse with the cover installed:

We had our first fatality today. One of the catfish was floating this morning. I think I'm going to have a second fatality by tomorrow. I didn't have a camera with me when I checked them tonight, but one of the catfish was pretty lethargic, but floating/swimming upright at the surface. It had yesterday's soggy food pellets stuck to it's dorsal fin, and to both of its pectoral fins. A friend was with me when we saw this, and both of us found it quite puzzling. We couldn't catch it to remove the pellets. The bluegill seem to be doing pretty well. They are coming up for food, and they seem quite active.

Since we had the fatality, we thought that maybe the project needed some better water. Some neighbors came over to see if they could assist.



The first hole was so successful, we decided we'd put in another one about 15 feet away. It was a real gusher!




















Actually, these are two 300-foot wells for a new geo-thermal HVAC system we are installing. The good thing is that if we ever need another water well, we know we have immense amounts of water starting at about 40 feet down. They were able to dig two 300 foot wells in less than six hours. But, the 55,000 lb., truck sure made some ruts in the yard after 2-1/2 inches of rain in the last several day.

When is the last time you tested your DO levels?

Not only DO, but I'd get an aquarium test kit and test Ammonia, Nitrites and Nitrates.

Ken,

Your catfish may have died from a spike in nitrites. The symptoms sound like that too. Scaleless fish are very sensitive to nitrites. Fish in the centrarchidae family are not. Yellow perch are quite resistant to nitrites too.

If it was me I would have felt better getting the fish tank cycled first before adding fish. But I can understand your time crunch.

Keep us posted. I am keenly interested in Aquaponics but haven't got my feet wet yet. A local high school that has one of my recirculating systems has it in a greenhouse, and they too want to give aquaponics a go.

Keep up the good work!

Your pea gravel is going to act as a biofilter. I was going to comment on the cycle thing earlier, but let it go. Your solids, without filtering them may become an issue down the road.

I tried some CC once that were given to me. Water parameters all good. I came to probably an incorrect conclusion that they just did not like the confines of that particular tank.

Good luck!

Cecil -- first, I'm really glad to see you back. Before I had the time to actually begin doing the physical work, I spent a lot of time looking at all of the stuff you'd written about your RAS experiments. I even resorted to looking at PeePonics in case it gets too cold to feed the fish!

Instar -- I haven't been able to check the DO in the past several days, as I don't own a meter. But a friend checked it earlier in the week, and we were pretty close to 100% saturation for the temperature. I don't remember the readings -- but he is a fisheries biologist who is into aquaponics in a big way, and he said it looked good.

[I am very fortunate to be able to volunteer at a WVU research facility, where they do aquaponics in a big way, and where I have access to some incredible experts, and equipment. Here is a link to the place: WVU Reymann Farm Aquaponics]

I do have a water test kit, and everything looks real good. My pH is right at 7.0, with virtually no hardness. Here is what my ammonia, nitrate, and nitrite levels look like (left to right) -- virtually nothing showing in the water. The ammonia sample is actually much more yellow that it shows in the photo.



A serious cold front has moved in, and the leaves are still on the trees. My water was at 54.3 degrees this morning, and the greenhouse was 40 degrees. Hopefully, the leaves will start to drop and the greenhouse will warm up.

Those numbers look good to me Ken, I have no idea what happened!