I'm still in the design/gathering parts/building phase of this project.
My fish tanks are housed in a 9'X17' insulated room of my barn. I have 5=275 gallon IBC's. They all have SLO that goes to a combined 2" outlet. One of the IBC's can be converted to a sump (incase the drain line to the greenhouse freezes).
My greenhouse is about 180' away from the fish room. It is 20'Wx40'L. I have not yet connected it to the fish room. I hope to get the trench done this fall. Inside, my plan is to build 2 flood and drain growbeds that will be 4'Wx38'L. They will both drain to a 4'Wx38'L deep water raft. The deep water raft will drain to the sump. I installed the sump inside the greenhouse, it is 3'Wx10'D. It has a threaded lid with a rubber gasket. I did this to prevent radon gas from entering the greenhouse.
I plan on using pea gravel in the growbeds with bell syphons.