After about a year of operation I wanted to make some improvements to my Big Aquaponics system. I decided I wanted to do Constant Height In Fish Tank, Pump In Sump Tank (CHIFT PIST) operation. I had been dealing with the need to clean my pump trap quite often and that didn’t line up with my “easy operation” methods I wanted to develop. So, the upgrade begins. A new big fish tank with a constant water level and an overflow out to the grow beds which would drain into the in ground tank where the pump would get to suck up basically clean water and avoid the whole by-weekly pump trap cleanings.
This new tank was built by connecting a couple cattle panels together to make a six foot diameter circle and then lining it with pond liner. There is a layer of tarp on the outside next to the wire and a layer of 1/4″ blue board between the tarp and the liner to give a little extra stiffness and insulation.
Folding the liner in and securing the liner around the top edge is probably the weakest point about this tank design. The folds in the tank provide a place where gunk can build up and it might be better to purchase a fitted tank liner that is made for the purpose. Unfortunately, those would be made of vinyl liner and I’m not sure how I feel about using flexible vinyl liners in this sort of situation even though you can get ones graded for potable water. I personally prefer the EPDM pond liner for aquaponic purposes because it is very durable.
It is possible that small fish in such a tank might be hidden in the folds and a dead fish floating in such a fold might not be found before it caused problems.
This tank has worked very well in the aquaponics system for a year and a half and I would do it this way again.