My second system is finished. Took a little over a month to finish up but in terms of total hours it was probably somewhere around 25 hours give or take. This system was made from 5 IBC's. One for the sump tank, one for the main fish tank, 2 for growbed/fishtank combinations, and one for a growbed/biofilter. The way this system circulates is basically the same thing as my first system (CHIFT PIST) but with a few slight variations.
This system only has one row of growbeds while my first system has 2 rows, the top row draining in to the bottom row. In retrospect I do not like that aspect of my first system because it makes the sump tank water volume fluctuate too much and I suspect the top row is hogging the nutrients a little bit. However, I also do believe the reason the bottom row is not getting as many nutrients is because the system is still not running at full capacity because I still only have 6 goldfish in there.
I cut a little over the top third of three IBC's forming three 100 gallon growbeds. These growbeds are fed by the main 275 gallon IBC fish tank.
The two growbeds closest to the entrance of the greenhouse drain in to 175 gallon fish tanks.
These 175 gallon fish tanks also implement the CHIFT PIST design and they drain in to the 175 gallon gravel filter.
The growbed closest to the fish tank (which has not been set up yet) drains directly into the 175 gallon gravel filter. Everything basically ends up in the gravel filter, which drains in to the sump.
Anyway, as soon as this system is done cycling I'm going to go and buy the tilapia. The weather is cooling down a great deal, and I really think that trout is possible over the fall/winter seasons. Of course you would need to aerate everything more than you would for tilapia but trout is so delicious it would be worth it in my opinion.