So I read enough on this site to realize I really need a QT/hospital tank. I picked up a cheap 10 gallon LED starter kit at WalMart for $35. Now I need a heater. Reviews are mixed on everything I read and many mention the heater overheating and killing all the fish. Does anyone have any actual personal experience on a good one? I prefer adjustable temp in case I ever have to increase temp with meds. TIA.