Temperature controller for canopy fans

[Hightower]

Has anyone tried using a computer fan controller with the temperature sensors on them and mod it to accomadate a couple canopy fans that would come on when the water temperature rises?

In theory it should work quite well. There just has to be a way of isolating the regular sensors from the saltwater.

a 12VDC adapter should be easy enough to find to power the unit.

Otherwise any other suggestions you have tried that work and are easy and inexpensive?

Right now my water temperature rises 3deg during the day if I dont turn on the canopy fans, but then the heater will also come on which of course is bad energy management.