Alternative to heatstick

I have been looking at most of the heatstick threads here at the forum.

What I really need the heatstick for is to do step mashing. I will not need it for boil, so I figured I could use a lower wattage element say 1000 -1500w. Basically I need to be able to heat the mash (5gal batches) 20-30F.

In my search I found this pond de-icer (1500W):
http://www.animalworldnetwork.com/icechasfloat.html
(Just an example, many like it out there around $30..)

Obviously I would need to disconnect the tempcontrol such that I can heat the mash (above freezing). I imagine it floating around in the mash using it magical heating powers...

Would this work?
At the price it seams like a good alternative to a heatstick?

Mads
117th Brewery

Is it food safe?

Good question... It is at the very least fish safe ;-)

It is of course not intended for high temperatures, but neither are the coolers we are using for mashtuns. Some of these are made in Aluminium, which would be better than the ones incased in plastic.