I've been looking through all of Randy's threads for substitutes for the Dow Flake and Mag Flake for his two part system. I thought I had read that there is a pool product that can substitute for the Dow Flake. While I know Epson salts can be used as part of the Magnesium solution, you don't want to to it alone as it add's sodium ion's out of balance. Is there anything else you can use?