propagation heat mat to warm my hydroponic reservoir

I bought a propagation heat mat to use to keep my 1 gallon hydroponic reservoir in my 26" high server case grow, warm at nights.
Has anyone done this before?
Has anyone got any advice before i burn my place down?

Thank

why not use a small aquaruim heater

Why would you want to keep the water warm? Warmth promotes algae and bacteria. The warmer water also makes it tougher for optimum water oxygenation. Is the water extremely cold to start? The optimal res temp should be in the 65-68F. And if you must go higher temps, NO more than 80F.

Its just at night here its probably getting down to about 55f. dunno if thats too cold. and i just got to the good bit.
My res is made of plastic and i didnt know if putting an aquarium heater in was a good idea. i do have 2 different aquarium heaters i could try tho.