Benefit of two heaters

[spit.fire]

I run 3 300w because anything less they have a hard time maintaining the temp on my system in the winter. Also if 1 fails it cannot overheat my system

[asylumdown]

I've got 2 300 watt heaters controlled by an Apex on my tank, which is about 375 gallons of overall water volume. I ran my display tank disconnected from my sump for 5 weeks once (i.e. with no heater of any kind), and on the main floor of my house I never had a problem.

I've never had heater issues on salt water tanks, but I would concur that they don't fail in the off position. I lost two entire planted freshwater tanks to that very problem. It's why I won't use any one heater that by itself could cook my tank