Originally Posted by wystearya
Because, as other people have already stated, the Tetra pre-set heaters WORK. I could have bought a CHEAPER adjustable at the pet store, but it looked fragile. I felt the Tetra looked like the better product, and as I said before, it has been working wonderfully for me. Last night the temperature outside was in the 30's, my house temperature was set to 68. Both my 2.5 gallon tank and the new 5 gallon were 77-78 degress. I check them both with the tank LCD thermometer and a digital meat thermometer I have. I know the temperature in my tanks are stable and plenty warm.
I'm sorry if you have had problems with pre-set. All I know is that the two Tetra HT10 pre-set heaters I have work great. At least in the 2.5 and 5 gallon tanks. They are supposedly good for anywhere from 2-10 gallons, though I might worry about using one in a 10 gallon. I'd go to the larger wattage Tetra heater.
I tried one for a while when i moved up from the one gallon bowl to a ten gallon tank. It kept the tank around 72-74* so i wouldn't recommend it for any more than 5 gallons.