Habitat - Outdoor :: hot tub heater?

[Myke]

I've seen a few hot tubs real cheap on Craigslist recently and got to thinking. Has anyone ever used a hot tub heater for an outdoor pond? I have an 8x2 foot blue plastic stock tank I am planning to make a pond out of. Living in Colorado, we can't count on consistent weather. Yesterday was in the 70's, today was 50 and rain. Anyway, the few times I was in a hot tub, it seems the temp was always over 104. I'm wondering if there is a way to regulate the temperature on them. Any ideas or reasons not to?

[marisa]

I'd talk to someone who knows hot tubs and get tell you about heaters and regulating temps.

[trudykurz]

I live in Texas but all the hot tubs I've been in have temperature controls. They are kept hot for our comfort but they can be lowered.