Heater wattage for 2 heaters in sump

[trilinearmipmap]

For a 120g tank (waiting for tank to arrive and ordering all the parts I need).

To avoid overheating due to heater malfunction I thought I'd use two heaters of a lower wattage rather than 1 heater of higher wattage. The alternative is one heater and then buy a controller to avoid overheating.

Also I thought I'd try the Won heaters because Ebo-Jagr's are too big to fit in my sump.

Is two 200-Watt heaters OK, my other option is either two 250-watt heaters or two 300-Watt heaters. The idea is if one heater sticks "on" permanently I don't want it to overheat the tank by more than 5 degrees or so.

Other heat sources in the tank will be return pump (either quiet one or Velocity T4) and lights (432 watts T5 pendant).

[Quagmire]

It's a good idea to go with 2 heaters.What I have is 2 heaters, each rated for 1/2 the tank volume.A 120g tank would be 2 heaters rated for about 60g each.This way you won't over heat if 1 gets stuck on,and you won't cool off right away if 1 quits.But always check water temp.as part of your daily matenance.Good luck

[Aquattro]

Yup, I agree. I run 2 x 200w in my 155g, total water is about 170 including sump. One heater can keep the tank at 75 F, so I'm safe regardless what happens to one. And check every day

[Aquattro]

Oh, and Quagmire, welcome to Canreef. Just noticed that was your first post

[Quagmire]

Thanks for the welcome Brad,its nice to find a local board.
Greg

[BMW Rider]

I put two 300W heaters in my new setup. It is located in my basement, so I want to be sure to have enough heater wattage to keep the temp up in the winter time. The total system volume is about 155 gallons.