Heater Question

[fftfk]

I am setting up a reef tank which I estimate is 120 total gallons of water. I am looking at the Eheim Jager 250 Watt heater.

For redundancy, I would like to do two heaters. Would I do 2 250 watt heaters or 2 125 watt heaters? I am worried 2 250 watt will cook my tank.

If I want to keep my temp around 79 what would I set the temperatures at? 79 on one and 78.5 on the other or both at 79.

Finally, and this might be a little more technical than a newbie thread, what do I do if I wanted to hook them up to the apex controller? Do I set them to go on at a lower temperature and just let the apex give them power when the temp probe sense the temperature is too low?

Thanks.

 

[thegrun]

Most of us have between 4 or 5 watts per gallon so 400-500 watts would be typical for your tank depending upon how warm you keep your house during the winter. If you went with 400 watts use two 200 watt heaters. Set your heaters at the minimum temperature you want to keep the water at, so if you choose 78 then that would be the temp you set, but be careful, heater thermometers are notoriously inaccurate. Use a good lab grade thermometer to calibrate your heaters, I have seen them off by 4 degrees. I let my tanks drop to 75 in the winter but if you want to keep yours at 79 that is okay. With a controller I set the first heater at 75.5 and the second to come on at 75. I have both heaters set to come on at 76 on their dials so they are sure to come on at the controller set points

 

[ThreeMoneyJ]

In my 120 I'm using 2 300w eheim heaters controlled by apex. The way I set my heaters up was to set them in a container of water with the apex temp probe. I then picked the max temp I wanted (80) and adjusted my heaters to turn off at 80 according to my temp probe. I then put the heaters in the tank and set my apex for heat on at 78.5 and off at 79. If the apex sticks on for any reason the heater will turn itself off at 80.

 

[fftfk]

Thanks for your answers!