Well I was at wallmart I asked the guy fi I could put a 100 watt fishtank heater(submersible) into a gallon ajr of water to warm up my terrarium he said no but he seemed in a bad mood(constipated) ) In anyones personal opinion what wattge for the saize of water in the jar like a 100 wat heater in a quart jar or whatever. I'd like the help my intermediates are slowly suffering.. And demand more that than cold days and cold nights.