HELP Temp Control Problems!!!

[nyyanks154]

The outside temperature here has been in the 90s recently and my tank temperature is rising quite a bit during the day, sometimes to the mid 80s while im at work. (its a 37 gal with 110 w of PC). I have a fan on the tank that, when turned on, drives the temp down, but often makes it too low, plus causes massive evaporation.
I know the best option is to buy a chiller, but lets face it, I cant justify buying a chiller in Connecticut if I only will use it for 2 months out of the year, plus I dont have $600 to spend on a chiller right now.
I was wondering if anyone knows of any thermostats that could turn my exhaust fan on and off to control the temp, or any DIY projects along those lines. Any other suggestions are welcome!

 

[dominican]

Do you have a sump? I had a similar problem, but my high temps were because the cabinet I built was fully enclosed. Bought an 8" diameter fan from Target and mounted it in my cab above the sump. Adjusted the speed until the temp stayed steady at 77. I stressed for weeks over the idea of having to buy a chiller before trying this. It really worked. Evaporation is a little accellerated, but that's the lesser of two evils. I'd suggest you get a fan with speed adjustment, and find out what speed works best for the temp you want.