I saw a request the other day about how to deal with high humidity in a GH and was curious about that myself since it rains in my GH during the winter. Just now it occurred to me that, while it would tend to decrease temps in the GH, if you took a small pump and circulated water (or anti-freeze) outside to cool it and back inside to create controlled condensation you could in essence have a cheap dehumidifier. If you catch the run off from the condensation lines you just put it back into your FT. Whadaya think?

Hi In your EMAIL I believe   you mentioned that you hadn't come across insulated I B C systems ? The first thing I did was to insulate the system ,cool in summer warm in winter .The grow light eight T 5 lights combined with sump tank give 12C- outside Tem 9C fish tank 19C -,going to install gas heating for G H ,simply the grow lights go out  at  night , the gas heater can maintain tem to about 15C .When it gets colder will send you readings .My first winter aquaponics .I like the idea of using freezers  good insulators