Benefit of two heaters

[HarleyC]

Gotcha.
Cheers!!

[subman]

Originally Posted by sphelps

BTW I also agree with redundancy like others have talked about but don't forget about control redundancy as well. If you run multiple heaters all large enough to do damage an external controller for temp control would be a wise addition.

yes! +1 I actually run 2 large heaters but they are controlled separate controllers

[HarleyC]

Good point subman. I have both mine coming off the controller through a splitter. Which basically means one heater. My thought was, if one fails, it will still control the other. If the controller fails, I guess that could be an issue as you would have no power to either heater.
Is that why you use two controllers.
tks

[subman]

I actually only use one heater the other is set to wait 45min before kicking in. If it fails off the temp has to be below the set point for that period of time before turning on. I can't actually see the controller failing to shut the outlet off, but I've been wrong before lol

[HarleyC]

Man! the multiple scenarios we have to put our brains through , just for some piece of mind and there are some companies making some nice coin out of our paranoia LOL

[gregzz4]

I'm kinda crazy on heaters, as others will tell you ...
Just look at my build thread
I have 3 x 200W on my RKE, and a pair of 250W on a Ranco, just in case
All in a 75g tank ( 110g total with sump )

I agree with everyone on the idea of using multiple smaller heaters, instead of one or two larger ones;

With one or two large ones, if one fails on, it may cook your tank
With one or two large ones, if you rely on them both, and they both fail, your tank is doomed

With two or three smaller ones, if one or even two fail, one will still be adequate to keep your tank going short-term
With two or three smaller ones, if one fails on, it will take longer for it to cook your tank

I set all my heaters in a bucket so they are max 81 degrees F
This way, if a controller fails, they won't cook my tank
Next, I installed 3 x 200W heaters controlled by my RKE
Next, I installed a Ranco controller, with 2 x 250W heaters set for one degree below my target temp, in case the RKE or such fails

Hope that helps

[The Guy]

Originally Posted by sphelps

It would take a while for a tank to cool off enough to cause problems, however for some reason heaters rarely fail in the off position. For this reason two small heaters is better than one large heater, however two large heaters is worse than one large heater. Hopefully that makes sense but ideally if a heater fails in the on position it shouldn't be able to cook the tank. Not so much an issue with external controllers.

I totally agree with this thinking and have never had a heater fail off when it dies, I only run a 125w and a 100w in my 90g with a 50g sump and it keeps my system at 80f. I plan on putting an external controller and make everything safer though. So I would say bigger isn't better in this case.

[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