anthropic, this thread is taking off!!! Thanks for starting it. And for prodding us into thinking of something nearly "out there".
I've waded into the FA mats in our pond and felt the much warmer water right in the mats. Something's going on there. The FA may be leading to solar gain; the mats may be preventing water mixing. Any shade the FA is providing may be canceled out by the apparent heat gain.
I like the tarp idea. Can you suspend it from floating supports? Can it be rigged in a manner that allows it to be lowered to the water surface to survive a wind storm, then returned to suspension after the wind is gone? Just thinking aloud.
I've contemplated black tarps to warm my pond, as the incoming water is from a trout stream, and I'd like my bass and sunfish to do better than they do. Tilapia are not feasible at this time.
