rocko,skiyd,eggs,you all learned have a point. but some chems WILL come out of solution and go back into saturation when the cools down, and go back into solution,some will not, for the WC, I am not a chemist nor did I do good in it, as Boomer told me all the abbreviations are from Latin, Nuns could not drill that into me!!!!!!!!!!! But my years at a fossil fuel power lab tech, and taking care of a boiler that runs at 2600psi super heated steam and any over too much chems in the boiler water goes into the steam and deposits on the turbine blades is disastrous, so I learned the chemistry I needed there. BUT I KNOW some chems will not go back into solution after précis out, I do not know all of them, and what is all in are salt mixes, but sodium hydroxide at 50*f goes to a solid and will NOT go back into solution again no matter how warm. I just suggest, warm your water first, add the salt over time, I do agree, I have mixed that my way got lazy on a WC, after mixed turned off heater and pump, it cooled down over a few days, BUT nothing came out of solution because it was already in solution, and reheated the water for a WC.