Tropical pondin cold climate?

[Demo]

Thinking (only thinking so far) about keeping a RTSN i saved, and making an outdoor pond for it, i could do it(digging by hand of course) but, the climate in North Jersey, gets pretty cold, its in the 50s right now, and the ground freezes over winter, in maybe 2-3 weeks. I know that there are pond heaters, but, are there any heaters that actually keep a pond HEATED? If so, what do i need, my idea of a pond is a hole with a tarp in it, fill with water.

 

[nickman]

youd almost have to use a swimming pool/hot tub heater to keep that amount of water warm enough in the winter, id almost build a greenhouse type cap over it at that point to keep some of the heat in. id imagine it would cost a fortune in energy, prob to the point where an indoor pond would pay for its self in a year or two.
not to mention the fact that it in the winter there would be steam coming off of it 24/7 and your neighbors would prob think your house was on fire at first. haha

from the reef forums the only outdoor tanks/ponds i have seen are in more southern states. its just too hard to maintain a steady tropical environment that far north. not saying it couldnt be done, i just think its a major uphill battle.

-nick