I have a Ranco ETC controller which is rock solid. Unfortunately, it isn't cheap. There is an amazing range of prices for the single and dual stage Ranco, ranging from $60 up to almost $200. I guess there isn't much competition to keep prices reasonable.
Here is a cheaper option which controls your heaters, but not your fans. And "cheaper" is relative... Personally I think these are all way overpriced, considering how simple the really are - just a thermistor, some resistors and capacitors, worth a couple of cents.
Nowadays most heaters have a controller built in, and that is really the best way to go: Buy a good heater, and it will heat based on water temperature. For cooling fans, you could add them to your canopy and turn them on with the lights. If you get something like the Antec Tricool, you can set them to higher airflow in Summer, lower in Winter. Or use a dimmer to control the amount of cooling.
If like to do things your way, here is another option. :smile: