I just set up a gorgeous 40 gallon acrylic breeder. however i cant get the temp to stay stable i brought a 150 watt jager heater and i set it at 75 last nite when i woke up this am the temp was 86.... im thinking the 150 watt heater is too much for a 40 gallon... any ideas? im just gonna go get a smaller heater to try after work. thanks