We need a lot more input on this one... I use a combination of BRS for magnesium sulfate and chloride / I used a combination of soda ash and baking soda at a ratio of 1 cup BS, 2 tbs soda ash, 1 gallon di water to make an alkalinity solution that doesn't affect ph. I will be switching to Kalkwasser soon to maintain ca, dkh and ph.
I came here in hopes to see what other people recommended for other additives.