I have 2-80 gallon plexi tanks they are both heated by 125 watt Ebo Jager heaters, if your tank is glass a 150 would be better. I think they are the most accurate and longest lasting heaters available. Visi-therms and stealth heaters are JUNK. It was easy to create conditions where I would have 8 degree temp swings with the Visi therm/stealth heaters. The same size Ebo heater didn't fluctate 2 degrees. I have tested almost every brand of heater amd Ebo's are easly the best....no chineese junk titanium heaters I seen so many of them fry fish and even start fires I cant count the times. I currently have 15 tanks totaling 2030 gallons. They are all heated by ebo Jajer heaters, the one exception is the 240 its heated by a Ehiem and they own Ebo Jajer. In the last 10 years I havent had an Ebo heater fail.