Setting up a new 110 gal tall freshwater tank and tried the Hydor ETH 300 in-line heater for the first time. I am running duel Eheim 2217's and have the heater on the return of one of them (had to heat and stretch Eheim tubing to fit on the ETH 300 fittings) and it is performing beautifully despite being rated for a smaller tank. Room temperature is 72 and water temp is 78 and the heater indicator light is rarely on when I have checked it.