Big Heaters On Big Tanks Neccessary????

im running a 240 gallon and a 150 gallon on a single 30 gallon sump that while running averages around 7 gallons in the sump and im running a single jager 300 watt and it does a great job and keeps both tanks around 79 with it set at 81. so because its heating a small amount of water at a time in the sump with the proper turnover, which im only running 3x turnover on both tanks, this eliminates my need for a massive heater or having to run multiples saving electric costs on large tanks. so in the end im running an almost 400 gallon system on a single 300 watt jager.

I would say you're fine as long as you check your temps daily.. I know i got burned by running one heater and almost lost all my rays one time.. My solo heater kicked the bucket and i didn't notice it died until my fish and rays started to act wierd.. I checked my temps and my water had dropped almost 20 degrees.. So needless to say i run 2 heaters on my tank no matter what now, just as a backup incase one dies again.

i do have a second one in there i plugged in today as a backup

I always go way overboard on heaters.... I like to be able to control the temp quickly, sometimes that fast temp change can spark spawning.

I also have my heater in my sump, but running at 1350gph it pretty much running as much as it would if it was in the tank.... I do like the fact that the temp stays the same thru the whole tank, not only half at proper temp because the heater is on that side.