Backyard Aquaponics
A place to discuss aquaponics

Looking around for economical solution to a 2000L + fish tank for an AP system. Can anyone see a problem with buying a poly rain water tank and cutting the top off it? Being round will it still be structurally sound without the top?

I was thinking something like this:

that's what I have, with the area between the ribs on top chopped out for access - makes it a bit stronger, easier to throw a cover over the tank, harder to fall in etc

Jase, I cut about 1 third of the top of mine and wish I’d only cut out one segment, or about 1/8th. In fact much of the cut away piece sits back over the top of the tank, and keeps light and rubbish out of the tank. The fish also like the extra cover. Harvesting is done fishing with line and hook.

The top has a nice shape to it. Would make a nice GB or a swirl filter.

Thanks guys - its looks like the way to go I think, I'm half way through reading your system thread steem. How many fish do you suggest this size would be able to handle - assuming plenty of grow bed space?

It will initially be out the open so yeah I think just cutting one or two segments out of the top for access might be the way to go - I want to put a shade sail or some kind of protection over it eventually though. I'm also thinking of sinking it about 30cm or so into the ground to help keep temps a little more stable in Melbournes changeable weather?

So am I!
100 fish would be a good number. The good thing is they grow as you learn, so you can start out nice and slow.

I dont think that sticking in into the ground by 30cm will achieve much.

Just a query regarding the use of these tanks, would it not be better to seal the inspection hole permanently and turn the tank upside down? Nice curved bottom would mean all the crud would move to the centre. You pay quite a premium for conical based aquaculture tanks.

Most conical tanks are plumbed to drain through the bottom to take advantage of the solids collection at the lowest point...

Means you'll either have to dig your plumbing into the ground... or build some sort of stand...

Humm... wonder if there would be any loss of efficiency with a Chift Pist and a tapered bottom...???

You maybe onto something there Burnsy Wonder if we rang the tank makers and asked them if we could order one without the inspection hole

Was thinking get a 5000 litre tank, rip it in half and you get two tanks. Should be not problem to seal the inspection hole and if you were really keen you could poly weld it. No need to plumb through the base for aquaponics, just use a sump pump sitting in the middle of the tank instead of at the edge.

The easiest install would be to dig it into the ground and wash sand back in around it to fill the profile. Not having a reinforced top edge could be a problem but you could dig sleepers in upright at intervals around the tank to provide support.

Should make no difference, infact if you were siphoning from the FT to the GBs it would be more efficient using one of these tanks as they are higher than regular AP tanks and therefore the increased head would give an increased siphon pressure, this should allow for greater solids removal from your conical base if you have the siphon inlet centred on the tank