what would be the drawbacks of using inorganic cal/mg solution with organic nutrients

Can you do it? Im using general organics biothrive grow and bloom but I dont have the general organics cal/mg. All I have is some inorganic calmax that I use in my hydro setup. Can I use this with my organic nutes for my plants that Im growing in a soilless mix? The only calcium and magnesium they are recieving is the shit thats in my tap water (130 ppm) but I dont think that stuff is good for them... I dont know. Is tap water a source of usable calcium and magnesium?