Putting my fish to work

ajames54(5)June 3, 2014

(I cross posted from the hydroponic forum)

This is my third pond in the last 15 years, at about 500 gallons it is by far the smallest of the three. The fish you see in the photo are mostly second and third generation Sarasa Comets. Despite the fact that they would like you to believe that I am starving them to death they actually have a pretty good life. This year I've decided to put them to work.

In the past I've added either water lettuce or water hyacinth every year to use up the fish waste that would normally go towards making algae, every summer literally bushels of green stuff would be taken off the pond and sent to the compost pile. It worked like a charm and except for a little bit of string algae I would get every spring, I was algae free. This year instead of wasting all those nutrients on inedible water lettuce I've added a new pump a bit more plumbing and have built an Aquaponic system, now I am growing plants we can eat rather than throw away.

The system I've built is really two different systems together. The first part is an NFT system consisting of four, ten foot lengths of PVC drain pipe. Each pipe is drilled for fourteen net pots either two or three inches in diameter. The grow media in the pots is mostly Hydroton (Hydrocorn) though a few two inch pots have coconut coir. Currently growing are Lettuce, Strawberry, Green Beans, Jalapeno Peppers, Cayenne Peppers, Poblano Peppers and a couple of Tomato Plants.

The second part is a drip system, each of the three boxes in the pic bellow holds a 38 liter Rubbermaid tote the lids of which have been drilled to hold six three inch net pots. Each pot is fed by a 1/8 inch drip line, currently the water is fed constantly and I hope to be able to get away with that because I am using the Hydrocorn as a grow media. In the boxes I have Scotch Bonnet Peppers, Cayenne Peppers, Sweet Peppers and Dwarf Tomatoes.

It is still early days yet but the plants give every indication of thriving and I am quite optimistic. One thing that has really surprised me is how much I can now feed my fish without worrying about the water quality. The fish now get fed more in a day than they used to get in a week and I still get 0 readings from the Ammonia, Nitrite and Nitrate test kits (yes I tested the test kits).

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johns.coastal.patio(USDA 10b, Sunset 24)

That looks great, both happy plants and a well-finished project.

    Bookmark   June 3, 2014 at 12:57PM
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Does the pumped water return to the pond after "feeding" the plants?

    Bookmark   June 3, 2014 at 2:45PM
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steiconi(12a-Big Island, HI)

Nice system!

I do the poor man's version of aquaponics;
my property is steeply sloped, so I siphon water (and muck) from the bottom of my pond down to soaker hoses in the greenhouse. Pond cleaner, plants happy!

    Bookmark   June 3, 2014 at 3:04PM
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Thanks for the comments!

CaraRose, yes the water is constantly circulated, the water is running through the PVC pipes at somewhere around 80 gallons per hour, each of the plants in the boxes has water running over the roots at a rate of about 4 gallons per hour.
There is also another large biological filter that has nothing to do with the plants, it was my original set up and it is running at about 900 gallons per hour.

    Bookmark   June 3, 2014 at 3:29PM
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waterbug_guy(Phoenix AZ (Melrose))

Nice setup, and good detailed info, thanks. I've been interested in aquaponics for awhile and been reading. Unfortunately most people only post or video the initial setup and then nothing. Hope you can keep us updated.

Plant growth would be a big help. The plants in the picture look great. How long were they in the system when the picture was taken?

    Bookmark   June 3, 2014 at 4:23PM
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garyfla_gw(10 Florida)

i made what is called a "Seep wall" using a 150 gallon aquarium Was pump 7 feet up and allowed to seep back to the tank. Only one major problem the plants grew so fast they constantly diverted the water aqway from the collection tank lol. One other problem the glass got broken. Is now used as a terrraium with out the seep lol gary

    Bookmark   June 3, 2014 at 5:47PM
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Waterbug_guy I planned to keep updating since this is still pretty much an experiment for me, I've done lots of different things not knowing what may work the best.

Most of the plants (except the strawberries) I started under lights in the basement, some in rock-wool, some in coconut coir, some in dirt and some in paper towel. They were all started at different times but I planned for them to be out by May 15.

The plants went in in batches starting May 1, it was still really cold around here so the first plants were the lettuce and the strawberry since they were the most able to tolerate the low temps. I also wanted to start slowly so I could better monitor what was going on.

By May 15 I had some of the peppers and a few Tomato plants in and we had two very cold days and a late frost. It killed some peppers and two tomatoes outright and seems to have stunted the others. The peppers I set out after the frost are much bigger than those that got chilled. The beans all went out only last week, because of the frost kill I had spaces for them.

I also planted some peppers in dirt in a raised bed to act as a comparison but only two of those survived the frost.

We have been eating Lettuce for over a week now, taking a few leaves from each plant every day or so.
Many of the peppers have got "fruit" and that is absurdly early for around here, the plants in the raised bed are budding but have set no "fruit" yet.
The peppers and tomato that did not get hit by the frost are obviously out growing those that did some of them have almost doubled in size since I put them out.

Problems encountered to date ...
1) 2 inch pots aren't suitable for tall plants like peppers or tomatoes, the strawberries and lettuce seem to be doing fine but the others threaten to tip over.

2) Squirrels like strawberry corms and will eat any they can reach, fortunately they DON'T like climbing on PVC.

3) Nutrient deficiencies, there are some nutrients that the fish waste is missing, I've already had to add small amounts of Chelated Iron and Epsom salts (for the magnesium) and I expect to be adding Potassium as well.

    Bookmark   June 4, 2014 at 9:43AM
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Update 2 (I must have forgotten to hit submit for update 1)

from missing update 1.. we had a few really intense rain storms that severely battered the plants I lost a couple of peppers and a tomato other plants were also damaged.

This photo is just over two months in on the experiment, all of the original lettuce has been eaten and replaced, other yields so far include:
1.5 pints of strawberries
approx 2 pounds of Green Beans
6 Poblano Peppers
dozens of Cayenne Peppers and Jalapeno Peppers.
The Sweet Peppers and Tomatoes are not yet ripe. The Fish Peppers, Habenaro Peppers and Scotch Bonnet Peppers have bloomed but not yet set fruit.

I have only had some beans and a couple of Jalapeno Peppers from that plants growing in soil, the other plants in soil are smaller and seem to be a week or two behind

So a few notes and one warning...

First the warning.

I have been surprised by the amount of root growth I am seeing, far more that in the DWC or Ebb and Flow systems I have in the basement ( in the basement there is far more nutrient available so the plants don't need such massive roots). I was concerned that the roots would clog the pipes and leak pond water over the deck, so I bought a float switch for the pump. Less than two weeks after it was installed I woke to find the pond 3/4 full and the pump off.
I believe that I could have avoided this if I had hung the pipes at a greater angle, I chose not to do so for aesthetic reasons, I will re-hang them next spring.

And the notes

1) I seem to have been over optimistic in the amount of plants I could reasonably grow using my existing fish load, I have had to add a number of fish (aw rats .. I hate it when that happens) and they are now fed in a day what I used to feed in a week.

2) In the mix of things I grew I chose some fairly hungry plants (tomatoes and peppers) and I find that I am chasing nutrient deficiencies in those plants. The Beans, Strawberries and Lettuces are all doing well.

3) Those plants that were started by a Nursery in dirt did poorly in transitioning to the Aquaculture setup, I believe they were root-bound when I got them, unlike the ones I started myself.

Because I am chasing nutrient deficiencies I am now adding the following chemicals on a weekly basis:
1.5 tsp Muriate of Potash (Potassium)
1 tsp Epsom salt (magnesium sulfate)
1/2 tsp Hydroponic "trace element mix"
1/2 tsp Chelated Iron
1/4 tsp Phosphate (I may be increasing this one)

Water Chemistry is as follows

Ammonia, Nitrite, and Nitrate = 0
Phosphate = 0 (I really can't see any change, so I feel safe increasing the Phosphate above.)
Total Dissolved Solids = 164ppm = 9 degrees Hardness
peak pH (at 5 pm) 8.2 (by test meter)

    Bookmark   July 24, 2014 at 7:10PM
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Very cool! Thanks for sharing!

We've grown tomatoes and watercress in our bog and stream - we thank our fish for their contribution as we enjoy the "fruits" of their, well, labor doesn't seem like quite the right word...

    Bookmark   July 24, 2014 at 7:54PM
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waterbug_guy(Phoenix AZ (Melrose))

Thanks very much.

This is another confirmation I've read (rarely) of fish food = plant food. There are a lot of setups on the web where they have 4 goldfish and a ton of big plants and never really say they're adding fertilizer. Many act like this is all magic. Even the pro growers with hundreds of tilapia have nutrient and pH issues and said the same as you, certain kinds of plants seem to do much better. Swiss chard seems to work well from what I've read.

I certainly don't think adding fertilizer is bad, or makes aquaponics a sham or anything...you're still using fish waste after all. But I wish a lot of the people posting on YouTube would be more honest so people could tune their systems like you have to get a good result which is all that really matters.

There's a large commercial enterprise out here in AZ that started out as aquaponic but ran into the same problem...fish waste alone really didn't produce as much plant material as they thought. They converted to using water from the tilapia tanks to just irrigate the plant crops which are now planted conventionally in soil. This solved lots of problems. Made the water in the fish tanks much better. They could adjust pH in the water going to crops to max nutrient uptake and they could add fertilizer without hurting fish. This is the type of setup I'm planning because I think it makes more sense in my climate.

Thanks again and hope you can keep posting. Although I think lots of aquaponic growers are adding fertilizer very few talk about it. It would nice to hear how that all goes. Balancing plant needs with fish needs.

    Bookmark   July 25, 2014 at 11:16AM
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Waterbug_guy I had some of the same issues with the youtube people, but even more I was astounded by those that talked of growing large numbers of Tilapia (or TROUT!) in 55 gallon barrels. Not to mention those that were selling these systems...

Even in some of the earliest Aquaponic studies I found they acknowledged that they had to add potassium, not only get a decent yield but but to ensure a reasonable quality in the yield they got. Interestingly plants with fruit are more sensitive to potassium deficiencies than the green leafy stuff, like Swiss Chard. Some of the studies/reports also discussed treating micro nutrient deficiencies symptomatically but I think in a lot of cases it was just assumed.

To be fair though, if done according to the same studies I should be feeding a specialized food 4 to 6 times a day, with a food weight of 3% of the total body weight of the fish population per day. Mine get something around 1/2% per day of a good quality Koi food.

One of the other issues I've been having is the amount of water I loose through transpiration, on a hot clear day with very low humidity I loose more than an inch, I would expect Arizona to be warmer and drier than here.
Now that I think of it if my municipal water was not so thoroughly scrubbed I might expect some of the required micro-nutrients from topping up the pond, but sadly not.

    Bookmark   July 26, 2014 at 10:13AM
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waterbug_guy(Phoenix AZ (Melrose))

The humidity here is severe, well under 10% in May and June. We are in our monsoon season when humidity gets above 30%. Some plants can suck up a lot of water. I grow a fair amount of stuff in no drainage hole pots and am amazed how much water some plants take.

The info you're providing is about the most impressive I've seen outside of just a couple of professional growers.

    Bookmark   July 26, 2014 at 3:00PM
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Final update, season is over and the harvest is in.. so how did the fish do?

I massively overestimated how many and what type of plants I could grow. I could not rely solely on fish waste as a fertilizer since there is no significant source for potassium in the fish food I had to supplement it. I also had to occasionally add trace elements, iron and magnesium being the most critical. My goal was to keep my GH around 200ppm (13dH) and KH around 100ppm (6dH), this meant that I had to add small amounts of Epsom salt, chelated iron and a hydroponic trace element mix every other week (originally every week but after the huge rains stopped I was able to back that off), next year I plan to target 300ppm for GH. The biggest issue I had however was nitrogen, despite adding new fish and feeding significantly more in a day than I once fed in a week I still ended the season battling a nitrogen deficiency. I just could not get any reading for Ammonia / Nitrite / Nitrate on any test kits and I even resorted to adding Potassium Nitrate to battle the deficiency. If I planned to have the same plant load next year I would need faster growing fish like Tilapia, Trout or even Koi. While I may add one or two more fish on the whole however next year I will grow a less demanding mixture of plants and if necessary augment with Potassium Nitrate.

Other items of note:
- 2 inch net pots are not suitable for anything other than lettuce, strawberries or similar low growing plants.
- There was no discernable difference in the growth of the plants started in rockwool, coconut coir or dirt except in the case of the plants started at the nursery which were root-bound when purchased and remained stunted all season.
- Tomatoes were not a good candidate to be grown on the rails, they suffered severely through wind damage and many were broken in the heavy rainstorms we had in the spring and early summer.

As for this years harvest, the Tomatoes, as mentioned, had problems and only a few fruit survived to ripen, though those few were tasty.
The peppers were another story, I got excellent yields from the Cayenne, Jalapeno, Poblano and Fish peppers I planted.

The picture bellow shows one of the Jalapeno plants from the rails next to one grown in dirt, both plants were started at the same time from the same seed packet, the one grown in the dirt was grown in a well fertilized raised bed about 25 feet from the one grown in the rails.

I have been growing peppers in soil for years and in our short season I would plant 4 to 6 Cayenne pepper plants to get enough dryable peppers to last out the year. The next picture is one of the 6 plants I grew in my system this year, the one shown was typical and I had already picked from it as many peppers as are on it in the picture, about as much as I would expect from a full crop of plants grown in dirt.

In both these photos you can see the signs of the Nitrogen deficiency, the almost white leaves in the new growth.

The Fish peppers were the big surprise, I normally grow them for the novelty factor and until this year I had never had all that many and had NEVER had one ripen, this year I have more than I know what to do with and the picture shows them in various states of ripeness, they really are quite attractive.

As for the rest of the plants even after eating a huge number I have about 5 pounds of green beans in the freezer, they did quite well and were vary easy to maintain. The lettuce did really well until early August when it all bolted to seed, as did every Lettuce plant I attempted to start after around Aug .1. The strawberries were nice to have but not all that productive.

One thing I didn’t really notice until quite recently was the fact that I didn’t loose anything on the rails to vermin. Normally I loose some of my crop to squirrels and some to insects but even though the plants in dirt took the normal amount of damage the plants on the rails had almost none, and the plants in the boxes had very little. You can even see on the picture of the Jalapeno plant from the soil the two peppers being eaten by bugs.

Finally to the health of the pond, as mentioned the plants took up all of the Nitrogen I could supply and only after adding Potassium Nitrate would I see any levels on my test kits, the same can be said for phosphorous, at no time could I get a measurable reading. The water remained crystal clear and there was very little algae growth on the sides of the pond. Because there were no floating plants with roots to provide protection none of this years fry have survived (as far as I can tell), but the lack of shade also meant that my one lily plant constantly produced flowers into September, in the past it has been finished by the end of June. The fish remain healthy and while I didn’t get any babies this year I also didn’t loose any adults.

    Bookmark   October 9, 2014 at 9:16AM
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Very cool! Thanks for the extensive follow up. And I do love that you grew Fish peppers. With fish!

    Bookmark   October 13, 2014 at 8:12PM
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