I grow in soil but luckily I've never (knock on wood) had any difficulty with plants due to water/nute/pH issues, just gnats which I took care of with gnatrol! Amazing stuff btw and I had Thrips once. I never measure soil pH. I just kinda look at the plants and if they appear green and are growing I never mess with anything. The only thing I regulate is my temp at the canopy and the pH of water I put in.

Does too much calcium prevent uptake of some other vital nutrients?