My central heat and air doest reach the upstairs well and the upstairs window units are not doing the trick to lower the temperature in the hallway although the doors are kept open to cool the area. I have cichlids, non-agressives, and a bgk. The water temperature is about 84 degrees during the day. As the summer gets into full swing the water could potentially raise to temperatures exceeding 90 degrees, so I need a chiller to prevent this from happening.