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?

Thanks

They are supposed to work with plastic trays so my guess its safe and it should work for a small reservoir. Depends on the plastic quality of your reservoir...you could at least test it.

They have fish tank warmers also that can go directly in the water, I think it would be more efficient not warming the floor.