I've used it in the past.
Worked very well, except it took in water.
Even though it sank it never took in enough to
cause short(s) or damage to fish. The reason
it was taking in water was the fine seal between
the two sections. This problem has since
been rectifide. I strongly recommend it.
Last year I layed out 2x4s across the pond, and
fastened plastic to them. Also kept one smaller pump
running all winter. No problems, no ice on surface
whatsoever, and no supercooling due to too strong
a pump. Didn't loose a single fish, our temperature
here in Ottawa,On.Canada averaged -40 it was
the coldest we've had in some time. Of course the
Heron which has since found my pond is trying his
hardest to reduce my stock.

Roger

Pictures of setup available upon request.