<a href=showthread.php?s=&postid=12062559#post12062559 target=_blank>Originally posted</a> by RumLad
I had a new thought today, possibly mentioned earlier (that wouldn't be a first on this thread). If the two heaters are placed close together in the sump, and the flow is relatively slow across the sump, could the heaters be heating a small volume of water (1-2 chambers worth) and then turning off? Only to then turn back on once the chambers have turned over yet again. Given the temperature difference between the tank room and the basement, this may account for the inability to raise the total temperature by more than a degree or two. If this is the case, RT6, you may get more bang from your heaters by placing them both in the main display tank for a while, until the weather warms a bit out there.
Again though, we can't really dive in until we get the facts we have been seeking ie - real temperatures, pictures of placement etc. Please stop adding livestock until the temp issue has been settled, okay?