Never trust the temperature settings on heaters. Use a thermometer to confirm, preferably the digital ones. I recently got a new heater and tank and set it at 79 without a thermometer. I was wondering why the temperature felt so hot so I got a Marina digital thermometer and the temperature read 88 degrees! I had to set it at the lowest setting 67 to get it to drop to 79. I got another heater (different brand) with a second new tank and another Marina digital thermometer and had to set the heater to 78 to get it to 81 degrees. So never trust the numbers on a heater.

I was hoping that he would have cheaper dats, though. 