Honestly if yur water wont kill grass on yur lawn yur good..it just dictates how much nutes u can hit them with.best advice is get a good tds meter(u guys go by ec but im anal so i wanna kno precise numbers which wud b ppm).theres alot of nutrients naturaly in water every plant needs..calcium,zinc etc...my natural well water is 225ppm so i just never nute over 75%.im n dwc so i mix 3 gal nuted,one straight water....done deal.