Chiller purchased

[James]

Well, I finally got tired of seeing 85* temps, sagging corals, and steamed fish.
I bought a 1/4 hp Arctica chiller $735.00. for my 55gal reef. Easy setup, no hard pumbing, and is fairly quiet, sounds like a small refrigerator. Has to be quiet because my tank is in my bedroom 5' from my bed.

I set the temp. to 80* to start and turned it on. It ran for a while and brought the temp. down to 78.5* and turned off on its own. The temp. over a while rose to 81* at 5:55pm and the chiller turned on and ran until 6:15pm and turned off at a temp. of 78.5*.

Is this normal operation for chillers?
Is it safe to have such a temp. flux in such a short time?Why did the chiller not turn off until it reached 78.5*, when it was set at 80*?

If anyone has exp. with these chillers, please let me now

[Nimic]

Most thermostats in AC type units will go 2 degrees lower then the set temperature. Otherwise they would cycle too often.