Thanks alot folks for your great input, helped alot, i really liked the blue planet Cal-Mag 2-0-0 cheaper and great reviews, but it was said by AN, that if you mix other NUT not from the same brand the PH perfect will be unbalanced, not sure if it's a sale point, because i'm not planning to Order PH up n down, just the PH pen as it would be too heavy for shipping haha, but if what Tyler said about Sensi being PH perfect only in RO water then i'm gonna have to get them somehow.