when you talk about TDS / ppm / ec

[Montana Mogy]

Ron hello, I have 2 questions. 1: when you talk about T.D.S./p.p.m./e.c., or other references to nutrient levels in the water, do you ignore the amount that is already in the fresh water, and add the amount of nutes? say you want a 400 ppm, and your fresh water has 150 (without nutes) do you add the 400to the 150, for a total of 550? being as one doesn't know what is in the water that you are starting with this has confused me. 2: I see you are using and selling a commercial nute, how did your tests with miracle gro, or the generic equivalent with epsom salts and calcium nitrate work out? did you grow tomatoes to completion with it? Thanks for the great site.Montana Mogy