This was one of the reasons i wanted to use the ESV. Seems like a very simple system, and the calcium part includes mag…That's too bad. Although most things seem to be ways to sell you more down the road. Let me know how the ESV stuff goes. I have the 2 part, but I haven't tried it yet. I'm waiting for the red sea to run out... or at least the red sea alk and then I will do a big switch out.