I cant remember the formula for adding gh to my ro/di water. All I can remember 3, 3, or 3, 3, 2 can anyone jolt my memory
(in the APC Sponsor sub-forum) this is the information on Seachem Equilibrium:
The ratio is about 3.3:1, Ca:Mg.
Equal amounts of CaCl (Air-Dri) and MgSO4 (Epsom Salt) will give you approximately the above ratio.
Obviously, if your sources of Ca and Mg are different, the amounts of chemicals would change. As for potassium (K) there is approximately 3X the amount of potassium than Ca. I used to mix my own GH booster, but now I buy just buy a good mix. I like Seachem Equilibrium because in addition to K, Ca, and Mg it contains Fe and Mn.