Most heaters are designed to have a swing of 2 degrees, so as not to prematurely wear out the contacts, so two degrees is not a big deal. As long as the overall temp. doesn't get too high, over 80F, you should be ok. If you are finding that the temp. goes up b/c of the lights, then do what you are doing, air it out. A another option is to buy a small cooling fan to blow across the top of the water. Last resort a chiller. |