We've had 2 nights in the 20s and the system is holding a steady temp, so fish will go in on Wednesday. We began the system with beautiful 6.5 water from a 7 year old stocked pond. In less than 1 week, the wonderful greenish water is running clear, so time for fish. We also had 2 pipes running over pebbles and have a great bloom of string algae to be part of our fish's diet. We also have started duckweed for them. We're pretty excited since we used pebbles rather than more conventional mediums for $$ savings. Seeds germinated pretty quickly in the pebbles. The net pots were filled with pebbles and just topped with a thin round of coco-liner. The grow beds only have the pebbles. Here are some pics and I'll post more when it's populated.
We got 3- 260 gallon totes from a cig manufacturer (glue comes in them) for $40. We cut off the tops, inverted them to make grow beds and scrubbed like crazy.
A friend gifted us with a pallet of black plexi that was used on a chicken farm (don't even want to know for what) to cover the sides & top of the fish tanks to keep out sunlight and lessen algae blooms.
The grow bed was framed from scrap, a liner was attached and we used foam, that lined a shipped box, as the float. 3" holes were cut, net pots dropped etc.
It's been a couple of months & we're still learning but the system is coming into it's own. It's an interest balance between the fish, their poo & needed nutrients for the plants. In retro-spec, I only wish we had started with more fish since the need for fertilizer is impressive. All in all, a closed system works. We are growing duck weed in a segregated flat, feeding it to the fish and they are growing rapidly.