My CH is in the 600's which I manage by keeping my pH and TA on the low side.
While not an emergency, I would like to lower the CH. Dilution seems to be the preferred method, but a recent Google search discovered some products that claim to lower Calcium Hardness (see http://www.protechpoolsupplies.com/S...ardReducer.pdf or http://www.intheswim.com/Pool-Chemic...dness-Reducer/ for example).
I've not seen this class of products discussed here. Do they work as claimed? What evil awaits my otherwise perfect water if I use it instead of dilution?