I've been trying to understand this for a while now and still now 100% on this. At the moment I have my heating sources on a dimmer, if i see a low temp, i turn it up, if I see a high temp in the tank, i turn them down. So essentially this is all he that is being accomplished in this thread is the construction of a dimmer for more then one light.

Now is their a way I could have my heat sources to heat the tank to a certain temperature and then stop? Just like on my fish tank, heater turns on if temp drops below 24 and turns off if tank is above 25, is this acheivable for a BP tank?