When I first started to grow I was always spun up about making sure that this or that was right....I finally found out that the MJ plant is a very sturdy plant and cant take alot. I found a simple solution to my problem. I live in the city where my tap water is 250-300ppm (Im using a hydro system).. I found that if I buy a de clorinator filter for the shower at Home depot, I can get all the water I need( till the filter runs out)... as long as the chlorine is out of your water, the plants will deal with the rest hince no need for Cal Mag and other like items. I also have better luck using Honey instead of Molassis in my applications... I tend to yield about 1lb per plant.... Mi dos centavos...Mx