I believe commercial Cal-Mag uses Calcium Nitrate and Magnesium Nitrate.
I am a home brewer and am used to adding acids to lower pH and salts to create brewing liquor in ppm per gal. I have calcium chloride, calcium sulfate (gypsum), calcium hydroxide (pickling lime), and calcium bicarbonate (calcium hydrogen carbonate), as well as Epsom salt (magnesium sulfate). Does anyone have a recipe for Cal-Mag using these salts?
Without a recipe I have simply been carbon filtering my tap water to eliminate chlorine then lowering pH using 10% phosphoric acid. The filter does not remove the 39 ppm Calcium and 6 ppm Magnesium in my municipal water supply.
I am just wondering if this is too much of one and not enough of the other. I am thinking a 6:1 ratio should be more like 3:1 in which case I can add 7 ppm magnesium by adding ~1 gram Epsom salt in 3 gal of my filtered water to bring the mag up. It will also add 33 ppm sulfate.