Backyard Aquaponics
A place to discuss aquaponics

How are the joins between the panels sealed?
Espeacially the ones between the sides and the bottom.

Haven't had a look in there for ages, but will try as soon as we get rid of the 2 feet of snow we got last night =/ Maybe I can just turn the tap and see what comes out.. =)

No checmicals, but the ones from the cows way back perhaps.. Some antibiotics etc perhaps, but should be long gone..

Either that or your fish will grow horns and give milk

After a few years any minor (30cm or less?) carbon-based sludge should certainly be pretty well oxidized down to nothing leaving some sand and minerals. I'd be surprised if you have more than a cm of mud in there. Any antibiotics would almost certainly have been eliminated by time/oxygen/water. Bacteria/fungi etc also would have helped take care of antibiotics once levels dropped so they could survive.

I'd open the drain, hose out the tank, put in some water, add sacrificial goldfish and see what happens for a week or so while you get the beds ready.

Hi BC. In Australia, we don't call that a tank, we call that a townhouse. They sell for about 350k!
I would think you would have little trouble growing out trout over a 6-7 month growing season. You could get a headstart with advanced fingerlings that have been overwintered, or just buy new season fingerlings as soon as they are available.
Can't wait to see what ur plans are for gbs.

(Is anybody else starting to feel a little inadequate?)

Thats in geelong round here they're 550K

Went to Ultrapanel today to look at there concrete panels to check out the possibility of using them to make a tank.

They wanted $11/m2 for seconds so they are not a cheap option for a tank even if you could seal up the joins.

So I think I'll place that idea back in the draw. Of course if anyone could get then cheaper than that it might be worth a go.

build a form and pour your own

Just hire a trencher
Dig the trench
Pour in the concrete let it sit for a few days then dig out the middle
Pour some more concrete

GB Idea: We have a ca 60x30 ft concrete flat surface with 3ft high walls on three sides that self-drains back into the tank. I could use this entire surface, or wall off section(s) of it.
I'm not sure how to use such a surface in the best possible way. I could make it into one large GB and build footbridges inbetween the plantings, but that would drain like half the tank during flood.. I'm more thinking of a combined NFT gutter and gravel GB's, sortof like King Erik did, I could also start quite small this way in a "corner" of the concrete surface and expand as I add fish etc, just get longer gutters and add gravel GB. Problem is this area has a 6m wall on south side..