Very helpful guys, thanks, but I have another question. Zandor says I can add CalMag if I am using RO water. Why can't I use it with well water? Should I just take it back? And how much Liquid Karma and Calmag do you guys add per gallon? Do you stick with the instructions or vary that? I am using Tiger Bloom for the basic flower nutes, if that matters. I would be happy to supply specifics on the Tiger Bloom if that would help, but I am leaving in a few minutes for 2 days.