I've been reading about the use of Lime to soften water. It appears that you can add lime to water as a flocculate to precipitate out calcium. I found this paper here:
http://www.ceegs.ohio-state.edu/~lweave ... tening.pdf
That discusses the use of lime to soften river water. It appears that you add the lime, the calcium will then settle to the bottom, then I would think you could vacuum to waste. or filter it out. If you had a centrifuge I guess that could be used to separate it out also.
Has anyone seen/heard of this for pools?
I've considered doing the lab described in the paper above using my pool water in the beakers instead of the river water to see what happens. As my fill water is both high in calcium hardness and alkalinity I've been looking for something that I could use to reduce the hardness as replacing the water does not help me.