Benefit of two heaters

[HarleyC]

I think I see what your saying sphelps - basically if you have 2 large and they somehow both fail, then you get a rapid rise. However, I do have the temp controller, so the odds of all 3 devices failing would be more in line with the lottery odds - no?

[sphelps]

Originally Posted by HarleyC

I think I see what your saying sphelps - basically if you have 2 large and they somehow both fail, then you get a rapid rise. However, I do have the temp controller, so the odds of all 3 devices failing would be more in line with the lottery odds - no?

With two large heaters only one would have to fail on to cook the tank which can happen faster than it cooling off and livestock tends to be sensitive to heat vs cold. Also two heaters means twice the chance of this failure mode. And yes external controller can help prevent it. Usually people set heater temp slightly higher than the external controller temp for added safety.

[HarleyC]

Gotcha.
Cheers!!

[daplatapus]

Yeah, that's why in my mind I prefer several (3-4) smaller heaters. I also have a basement sump that sucks the heat out of my system. If one fails on or off, no big deal. On a 200-300 gallon system, if one or 2 even, get stuck on, definitely needs fixing, but shouldn't cause a catastrophic failure.
But that also means you have to pay attention to your system. You don't want one broken heater to be doing all the heating You should know if they're switching on and off.