Temperature Fluctuation

[Myka]

Psst! Hey Brad, his swing is 2.0 degrees...

Personally, I wouldn't want any more than 2 degree fahrenheit swing, and yours is about 3.6. I would not find that acceptable. Your daytime temperature is already up to 81.5 degrees, and I wouldn't want it going much higher than that. If I were you I would add a good sized fan blowing across the top of the water and/or onto the bulbs. I would keep a close eye on it as the weather warms up, as I think you are going to have troubles keeping the temperature down if it's already that high now.