Aquaponic Gardening

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I'm hoping to glean a LOT of useful information from this friendly site!

I found out about Aquaponics  from a recent Worm Farming Secrets newsletter and immediately started brainstorming on a system for my back yard. One of my co-workers has been trying to give/sell her 8'x2' stock tank for the last five years. Well, I guess God had her hang onto it long enough for me to acquire it! It's now in place, but I need to coat the entire inside with a good sealant graded for continuous underwater use. I found out that 100% silicone is not good when used on galvanized metal - drying agent is corrosive (could be why there is seepage along the bottom seam where silicone had been previously applied). I'd come across a DAP Auto/Marine sealant that appeared to be what I needed, but, alas, the online info indicates not to use it on galvanized, I'll be taking the tubes I bought back to Ace.

There's a product out of CA that claims to be non-toxic, rubberized, and fully useful for sealing stock tanks, fact, there's a YouTube video demonstrating its use on a rusty tank. I'm now looking at using Tucson Rubberized Coating typically used for roofs. Talking with the rep seems to indicate it should be safe.

QUESTION: Is anyone currently using this coating in their tanks? I'd like to do the coating really soon so I can acquire my Tilapia before the weather gets too much cooler.

Thanks! Looking forward to getting to know folks here!

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Hi Pam,

Never used those products before so i won't be able to offer any advice, but, i can suggest an alternative.......... you can put in a poly-liner. It can be ordered to size, or you can save some money by DIY'ing it yourself. 12 mil or thicker, greenhouse poly works well and simple enough to install.

Thanks, Harold. I have a very large roll of 8mil (I think) poly/plastic that I've started the makings of a liner...but I still need a below water line adhesive/sealant. Otherwise, as much as I don't want to, I could just cut about a 15'x15' section and push it down into the tank...seems like that would be a little unsightly, but I may just have to do that.


I appreciate your thoughts, though!

I like Harold's idea of poly liner, but I've seen people use old rolls of rubber roofing underlayment against dirt in ground ponds with no problems. I'm new at this too, but I'd suggest some sort of homemade corner molding to go under the plastic or rubber to round the bottom of the tank out. It would make it easier to clean and you wouldn't have to worry about rust poking through the plastic. Even if you go with the liner, I suggest coating the tank with primer at least.

Hi Pam,

I'm assuming the tank is round. If you place the liner material in the tank, you can make little vertical folds while the tank is being filled.The water will press the liner and folds against the tank. You can trim the excess at the top, while leaving a few inches of material. Fold the excess along the outside, and as an inexpensive solution, run some duct tape(overlapping layers) Finish with some zinc coated binding wire to tighten the liner against the outside face of the tank. You can also use a binding strap.

If you are worried of the pleated pockets created in the liner(anaerobic zones), put the return water line at a ninety degree angle in the tank to create rotation and suction line at center(see pics on my page). The water movement will suck more oxygen into the tank and remove most, if not all solids, as well.

A good greenhouse poly can last for more than 5 years this way, especially if you shade the FT.

Thanks John and Harold.

The polyliner was on my original-thinking plan, so I'm glad to have the encouragement.

I'm going ahead with the following:

I've purchased the 501-W-P Patching Compound and sealed all the seams, inside and out. After it dries by around 6 this evening, I'll coat the entire inside with rubberized sealant. Until then, I'm cutting a 20'x20' sheet of liner and lay it out so the sun will warm it slightly to help smooth out the fold lines. (The roof might be a good place to do that!) Tomorrow afternoon, I'll center the liner in the tank carefully creating the pleats on the sides. As the tank fills up, it may be easier to monitor that process. I want the rest to overlap considerably because I will be insulating the outside wall of the tank with 1" styrofoam, and the liner is to extend over the styrofoam.

I like the idea of the return line creating the water movement and had been considering it, but I'm glad you brought up the fact that the water should rotate with the folds rather than into the pocket area. Of course...that makes sense. So much to consider in the planning stages of one of these things that it's easy to leave out some of the details. (I'll take a peek at Harold's pics after I post this.)

I'd like the environment to be somewhat 'natural' for the fish, so I'll be adding rocky hiding places and some gravel on the bottom. And I'm also working on the shade/cover item because our neighbor has one of those chinaberry trees which are very messy and a lot of the leaves and berries end up in my yard...this is not something I want in my tank. (I've heard the berries are poisonous, as well.)

As we, in AZ, do reach an occasional overnight freeze I'm working on a couple of solar water heating formats...when I get to that point, I'll probably bounce those ideas here someplace.

I'm taking pictures as I go...will try to add a couple here for this post.

Hi Pam,

I like you idea to have a natural looking, eye pleasing FT. If you use a minimum amount of under gravel and have adequate water movement, you won't have any problems with anaerobic zones. Although, with a liner, sealing the FT is not necessary, but if you are anything like i am, it is a good idea. Hope it turns out to be spectacular!

Hi Harold,

Thanks...I hope so too.

Part of the reason for all the sealing is because the tank is almost 40 years old! When we put about 6" of water in to test where it does/does not leak, we found a lot of 'weeping' areas...not rusted, just weeping through. (weird) So, sealing to deter any further damage.

I got the inside coated this evening...just as I was running out of daylight. I didn't get the liner cut...too bush fixing the front porch light and making an attempt (ugh) at housework...didn't get much done in the latter...but hubby will have light when he gets home from work!

I looked at the pics on your 'page'...KEWL! Looks like someone else likes to play with PVC to see what can be done with it!    I really like the aeration from the PVC hoop! Is the flow pressurized in any way, or is that just from the normal return flow?

Thanks for your input!

Hi Pam,

The pump, as you can see is center bottom of the FT (submersible type). Its bypassed into the spray-bar before making its way to the GB's. Its really not necessary to add the spray-bar as the return flow creates circular flow from the periphery (surface) all the way to the center (bottom), drawing all the surface oxygen through the entire water column and into the pump. I got the pump free and it was slightly over-sized, so the spray-bar was needed to reduce the flowrate going to the GB's, which is great since there will never be a case of too much aeration!


Ah...good idea. I filled my tank last evening...added some Tap Water Conditioner, 1 Grandson, and 10 goldfish. I would post the pictures, but the batteries keep dieing in the camera...will load when charged. I noticed the strong flow coming out of my pump and was wondering how that might affect the grow beds, etc. The set-up you have should provide a nice option!

This morning, they appear to all be doing fine (Grandson was really wiped out last night!). I had some dental work done this morning and when I got home, one of the goldies was stuck on the screen I had covering the pump intake. It has quite the hickey, but seems to be moving around okay-but I don't expect it to last the day. As I was finishing up folding the pleats on the side, I noticed what was left of one of, down to 9. I fashioned a temporary filter by fitting some old pantyhose over a big wire basket like the golfers use on the driving range. I snugged it around the cord and expelling port and it seems to be doing the job. I'll try working on a better version when I'm not so impaired by the meds from the surgery.

Maybe the batteries will be charged after I take a bit of a nap, and I'll download the pics...(yawn)...

Hi Pam,

Not sure if you have a submersible pump or suction line in the FT. Good fix with the basket, but its not a really good idea to have metal in the system. Either way you can if you'd like, use a plastic bucket with a cover, and plenty of holes drilled all around the exterior. Make a snug fitting hole for the pump/suction line in the cover. The holes in the bucket will obviously provide much less suction than the bore of the suction line alone does, preventing the fish from getting stuck. Its better to address it now before you put in the intended fish.

Get some rest................ then go get to it!

Hi Harold,

Less tired, but jaw will ache for a while...

Okay...I'm not as groggy this time. :-)   Camera batteries are charged too.

The pump is a Cal Pump it for a song on Craigslist. The wire basket is one of those coated ones we've use for collecting eggs, so no exposed metal.

In my mind's-eye, 'the plan' is to use a 5-gal bucket (pretty sure I have the lid for it too, if needed); but, tell me if you think this will work okay: I have access to blocks of spongy shipping foam which I planned to cut up into smaller chunks - maybe about 3" squares or so; cut a whole in the side for the intake pump line (pump to be on outside of bucket) (yes, I'll remove the metal handle); weight the inside of the bucket with a brick; loosely fill the bucket with the foam and cover with a woven paint strainer I have. Hopefully, this would not decrease the suction too much, yet provide a safe, easily cleanable system:'s the one from last night of the Grandson 'swimming with the fishes':

I have a couple of errands to run, then I'll check back to read your thoughts on my proposed filter.

Thanks, Harold!

Hi Pam,

I see you're very talented, with the wire basket an all!  Yes the bucket will work. But I'm puzzled, all that filter material..... . If its just a suction line from the FT to the pump, you can simply put a screen mesh over the pipe end, or an end cap with many small holes in it. The bucket with numerous holes along its body is usually used when you have a submersible pump in the FT. Its not necessary to put filter material in the FT and beside, with all the bio slime and poo build-up, it would have to be cleaned frequently. Please, can you explain some more to me what your goals are? BTW, almost mistook your Grandson for a fish

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