Hi Gigaguy.
I'm using the larger mixing tubs as my GB's. I'm not doing flood and drain though. I covered mine with shade cloth, to help keep down the algae. I'm not sure if it will help keep the temp's down. You can see in the pict, that it's black. I may try to find something white....fabric of some kind...?


My 'homemade' bulkhead fittings are made from 'electrical' (gray) pvc fittings. The female and male adapters will go together, because the threads are 'staright'. The plumbing (white) pvc have tapered threads. The plumbing pipe will fit in the electrical fittings.

I think your green house may get too hot, even with both doors open (?) A solar powered attic exhaust fan, from one of the DIY big box stores, would be sweet.

When Stucco asked if your system was 'cycled'....I think he 'may of' meant ....Has the water gone through the natural process of building up the bacteria and nutrients...and is it balanced (?) PH level...nitrate levels...nitrite levels...ammonia levels...?
A nice 'fresh water' test kit is a 'must'.

Check out the first few pages of urbanrunoff's thread.....you'll see they are talikng about 'cycling' of his water. Here's the link.....
Urban's system


In the picture of your blue FT, the outlet is towards the bottom. Is this the height of your water level ?