Backyard Aquaponics
A place to discuss aquaponics

I am new to AP, and sure for some reason felling strongly that I simply must get involved with this as a next step.

It seems daunting but I do have great prior fish keeping and gardening experience. Any help and suggestions really appreciated as I am doing something it seems is fairly custom...

As I am putting the system into a rather small back yard area, and want to get enough yield from it to make it very worthwhile for a large family, I am designing my system with an in-ground tank. It seems so much less expensive and intrusive to put the fish in a pond rather than a raised tank and I am really surprised nobody else seems to be doing this.

It will be a thing of beauty once done, and because it is in-ground and so large the temperature, pH and etc. will be very stable and a much more ideal for happy fish. As you can see from the photo, there is an adjacent chicken coup which will supply fly larva for the fish and, if necessary, nutrients for algae and duckweed growth. Also, the top of the chicken run is an ideal location for thermal solar to heat the pond if tilapia are selected.

Several questions come up at this point for me:

1. In-ground pond dimensions will be approximately 4' x 4' x 12' or about 1,500 gallons. The hole is currently 5' x 5' x 14' to allow for construction. Or, I might just put a pond liner in and keep it the larger size for cost and functionality reasons. I hope to be able to drop a pond liner backed with several layers of used billboard plastic into the hole and edge it nicely with brick and rocks.

I have a good source for 30-year rubber 45mil EPDM and the pond would end up costing less than US $200. The soil is level and quite compact, and as the tank will never be drained, should stay in place well, or I can always redo it in a few years if it needs upgrading for any reason.

With bunk bed style grow beds I can easily have a couple hundred square feet of grow beds immediately adjacent to the pond which should allow me enough fish and plant density to easily feed family and a few neighbors.

2. It seems like the ideal design would partition the pond into at least two sections and pump from the bottom of the bigger section into a smaller solids removal section, back out to a bio-filter and up to the top GB level. Output from the GB into concealed sump at the lower back of the GBs and back via a waterfall into the big section of the pond.

Will it be difficult to raise the fish solids from the bottom of the big pond to the removal pond and how best do I accomplish this? Should I plumb in a 2" or larger drain pipe at the bottom and pump up from there? Can the solids bed just be filled with gravel and worms? Does it need to be drained ever?

Any thoughts a help. Glad to be here!

Lawrence

I used rubber 45mil EPDM in a partially underground/brick bed. Worked well! My only advice... don't drill a hole in it... after it's laid... and filled with gravel. Yeah that was dumb.

I'm still a newbie myself, with a 3-week old system, but here are my thoughts.

I wouldn't split the pond at all. Pump your solids into the growbed and the worms/bacteria will break it down. I also don't see why you need a sump other than your FT. Just pump the water/solids into the grow beds and let it drain back into the FT (flood and drain or constand flood).



If your pump is in your FT (as will prob be the case for you), the pump shouldn't have any trouble moving the solids that are near the pump. The prob you might run into w/ a pond that shape is that solids will build up everywhere else. This is why so many people opt for circular FTs. If you can create a swirl w/ returning water, solids will naturally move toward the middle where you'd stick your pump. I have the same sort of prob w/ my 2 IBC FTs.

I guess the size of the pipe would be whatever's needed by the pump. I have a 1200 gal/hr pump that comes outputs 3/4". I plumbed w/ 1" PVC.

Grow beds are filled w/ some kind of media (pour vinegar, if it fizzles, it'll mess w/ your PH). I use 3/4" river rock. I added red worms from my little worm farm, but I've heard that worms will find your beds if they're filled w/ yummy fish waste.

Being another newbie, I have no idea if we'll need to clean the grow beds. Good luck! Looks like a great start! and welcome!

Must be very exciting to have a new system up for the first time! Thanks much for the reassurance, and your tips are very helpful too!

My thought on the solids removal area was that it would help support a larger fish density. I am new to calcs, but the tool I downloaded says that with a couple hundred feet of grow bed I can put about 200 fish into the 1,500 gallons, and that's low compared to the normal 1:2 or 1:2.5 ratio experts talk about. I was figuring to have something more like 750 to 1000 fish by giving up about 5% of the FT for dedicated solids removal. Not sure this is realistic though.

1) As far as raising the solids, I do plan to taper the bottom to a collection point. Any idea how much taper is desirable?

2) Also, the pump will need to raise the solids at least five feet if into the solids tank, or 10-12 feet if up to the GB. Is that much lift going to be an issue for a standard pump?



I have heard repeatedly to use EPDM or Tigon and not to use PVC as it puts out some chemicals, but other people say it's fine. Haven't priced it out yet, but guess PVC is a bit less expensive and possibly good enough?

I built a pond to hold my fish. link in my signature. concrete and brick construction, with a waterfall for a little extra airation/aesthetics.

Here is a basic outline of what I am proposing. Does it look OK?

Can see from this design, I cannot return to the bottom of the FT because the water pressure will be too great, even with the 12' drop. So... no swirl unless i add a second pump. I understand a second pump is a no-no and will have to return the water to the top of the FT.

Your system is stunningly beautiful and looks like an incredible amount of work! Did you resist going completely underground to keep people from going into the pond?

Would love to see an update with photos of how it finally turned out. What material did you use for rendering?

yeah, mostly to keep people and the dog out. I'll try and get some updated pics over the weekend. it was rendered with cement and sand, and then coated with a potable waterproofing membrane. in the end, I could probably have done a lot of other things, but it worked out OK this way. If I ever repeat it, Ill probably try and just render with waterproof render, rather than coat it afterwards...

Hi there IV,

I think you might want to start by trying to do an elevation diagram to see how flows and heights are going to work, I really can't see how it's going to work laid out as you have it... And I'm not sure exactly how your gravel/worms solids removal will work, I think you may find that you get anaerobic muck there pretty quickly. Perhaps keep the gravel out and just make it a settling tank or swirl filter. But you probably want this and your biofilter higher than your highest growbed or your pumping isn't really going to work efficiently.

Very helpful advise. I will get a thinkin on it!

It's not the solids that make the water bad for fish. The solids produce ammonia (dissolved in the water), bacteria convert the ammonia to nitrites, then nitrates (both dissolved in water). It's the ammonia, nitrites and nitrates dissolved in the water that will kill your fish. To have a healthy system, you have to have enough bacteria to convert Amm to nitrates AND have enough plants to eat the nitrates, thus cleaning the water. If you are stocking a higher density and removing solids as you say, then you will have to remove the solids (fertilizer) from the system completely and throw it away so they don't generate more amm than the system could handle. A better solution in my mind is just add more grow beds, so that amazing fertilizer doesn't get wasted.

Granted, if you wanted to capture extra solids and put them on a soil garden or something, that's a great idea.

Again, it's all coming from a fellow newbie. Good luck!

Hi EB! Such a good idea! Here is a first try. I overcome some of the one foot drop limitations by just pressurizing parts of the system. Is this a reasonable approach?

I took the gravel out and reworked the filters completely. How does it look?

Yes. This is exactly what is needed! Thanks ever for your great inputs.

I don't think I'd put 2 pumps in this way. It would be really hard to get them synced up just right so you don't drain or overflow the fish tank. Could you just have the ST over flow off the top to the fish tank?

Also, you show solids in your ST. If your GBs are filled w/ gravel, you should have clean water coming out. Maybe you are talking NFT (I do see them tilted in the pic). In that case... do you have any biofilter?