This is what i did with my controller, i bought this:
http://oceanaquatics.com/store/produ...er-Controller/ then hook up a 120v relay, then hook up the fan to normally close on relay.
The operation will be:
1. Temp controller on= heater on= relay energize, fan off
2. After reaching desired temperature= temp controller off= heater off = relay de-energized = fan on since it is connected in normally close..Basically the fan will only turn on when the heaters are off..
This is the cheapest for me and it works.
tedy