I am just getting all of my ducks in a row before I commit to anything. I am considering getting a 300g stock tank (Rubbermaid, 69 in. x 63-1/4 in. x 25 in.). However, being in Michigan, the winters can be quite bad. This winter, not so much, but a few winters ago we reached far into the negatives. Since this tank would be too shallow to stay unfrozen, what would be the best way to keep it warm? Would aquarium heaters work?