I moght run into issues with heavy calcium eaters but i havent had a problem yet, probably because the nitrogen in fox farms comes from calcium nitrate, i dont know, but its working for me, and after looking at other base nutrients its the only one i found that didnt have calcium, aside from the nitrate form which doesnt count, i dont know why. At least until i get an RO system ill stick with what im using. Maybe the calcium carbonate becomes something else once in the solution with all the chelates, i dont know. But its working for me not adding extra calcium for now.
@Mossy was mentioning how magnesium helps make calcium available in the human body, maybe a similar chemical reaction is occurring in the plant?