[Delphinus]

Hi, cool topic, I don't really have anything to add to the controls side of the conversation, but ...

BUT, with three heaters in your tank running parallel, now you have three times the chance of getting a malfunction heater.

'tis true, but I think what is important to realize is that if any ONE heater fails, it is not going to do any damage (or at least "not as much"). So, the risk of a failure is more, but the risk of potential damage is mitigated. So goes the theory, anyways. Unfortunately there is never any way to make the risk an absolute zero, it's all in the way we play the risk management game.

But that said, I agree that it would be VERY nice to see an inexpensive solution that could be applied to heater control without a multiple-hundred-dollar investment.