8O My son comes in the house this morning, (mid you I'm always after him about checking his tank) and says to me " why is your tank sitting at 76 degrees"? Now I know better than that, I have this Visa therm 300 watt in my sump and it stays right at 81.7 constantly. So I check it and sure enough the mains down to 76 and the sumps down to 77. one look at my heater tell the tale. Busted, cracked right down the middle, Grabbed my 150 and my 100 that I keep as spares and stuck them in. The goo dnews is Marineland is replacing my heater FREE. I had one stick on once and they replaced it but to replace a broken one is amazing. Still don't know what could make it crack though, it's in my sump 2 to 3 inches off the bottom, and nothing around it to cause a problem.