I agree with your comments Don and Lynn. I have a waterfall and I use a UVB during the day and a moon bulb at night. I found before I had the moon bulb that I would get a higher reading at night but since adding the moon bulb the tank is consistantly in the 67-74% zone. I do have to say that I am scared to rebuild my tank cause I do not think I can build it to maintain the temps again as well as it does now.