I just left my local grow store and was talking about some nute issues I'm having with my girls. I am having burn or deficency problems even though I have been using Advanced Nutrients online calculator at medium to low feeding schedule. He is saying my problems arnt due to nute issues but to my tap water even though my pH is about where it needs to be. He was telling me I need to purchase one of his reverse osmosis products and AN's Revive before my problems would go away. By the way, my tap waters ppm is around 400. Any advice guys?