Whoops, sorry. It's DWC
I couldn't afford an air cooled hood on top of the light, tent, ro system and all the other random things. What's funny is the tent isn't even closed right now, I have the door completely open and a big oscilating fan blowing into it, res temps are still 80.
I will be adding a 265cfm dayton for exhaust, and 2 6" duct booster fans for active intake to try and help... but I predict the temps will only increase once I add those fans and close up the tent.
I imagine the res is getting warm because the buckets are black and the light is just sitting there slowly heating it all day.
Thought about adding some hygrozyme in there, not sure though.
Success! Once I got my tent and put everything in it my res temps shot up to 27-29c! But, I have dropped it to a consistent 23-25c (74-76f) by putting a piece of black/white poly over the top of the bucket. I also put a small fan at the base of it and switched out the HPS for a CMH bulb, the CMH tends to 'throw' less radiant heat at the plants. I think the real winner in the trio was the white poly on the top of the bucket, but all helped. Thanks for your help fellas