Quote Originally Posted by cigarettes42
Right now I'm debating on wether to get a Res. Chiller or AC for my grow groom. It's getting hot and I'm now always throwing ice blocks in my Res. And was wondering which would be more effiecient, "cooler res. or keep ambient temp lower?
Having been thru resivoir heat problems before, I can tell you what I have found. The greatest factors on rez temps are 1) the ambient temp of the room the rez is located 2) the pumpimg of air thru the rez.

1) Take any bucket or resivoir and fill it with cold water and it will naturally rise in temp to room temp without anything else happening. If your light on temps are 85 the rez will soon be that, and the cooler dark period the temp will not go down that much.
2) Pumpimg air thru will increase this temp rise even more. Your air pump is taking ambient temp air (85 room temp) and compressing it which adds heat to it. Now you are pumping 90 or more thru the rez which will quickly add more temp to it.

Crabby is correct that the "above ground" part of the plant can tolerate more heat then the roots, but the ambient temp effects both, for reasons stated above.
Tiny's point is also correct, if you just need to get the rez temp down the chiller will work, and they use less energy then an A/C.

If you expect your room temps to continue upwards from what it is now then that will also become an issue along with the rez. then the A/C would make more cents (pun).

Only you can figure out which will be best for your situation. I'd start by locating the air pump outside the room to a cooler location, that plus the added tubing run might help bring the rez temps down, some.