Heating 300G 2 aquariums same sump

I just started heating 151G last night with a 300W heater. My 120G has a 300W as well. Hoping that the 120 will stay st 78. It dropped down to 75 and I cranked it up. Still heating but the degree hasn't went up. Once the 151 gets to 78 I want to start the pump and run the draw from the main sump and have the 151 running together with the 120. What do you think, is 600W total enough to heat the system? I imagine the external turbo pump will add a little heat as well. In the basement so the room temperiture is lower than room. Uggghhhh! It's a long drive to get a heater. Hoping this works:frustrat:

Picts

Heaters are the most common thing to break in this hobby, i would use 4 heaters so you have plenty of back up in case one blows out.

I agree...I'd be running at least 3-4 heaters in that size system...it'll help the longevity of the heaters and also on the electricity used.

I agree 3 to 4 heaters.. will need at least 1000 watts to make it efficient..