Hope this doesn't come off as too odd of a question but is it possible to go "too big" with your water source/fish tank on an aquaponics set up? Before I get into too many details I've got access to a 12' wide, 6' deep round poly tank that has the top all messed up so I'll have to cut it at 4'. I just don't want to cut it and sink it into the ground and find out that it was way more than I needed.
You need to balance the fish waste to the garden grow space to make it so the plants get enough fertilized water but not too much. But water space itself is great. I have a hot tub that's 8' round. You should have a depth of at least 3' for tilapia I've heard.