havent added anything to the soil but Pro mix and from what I under stand is that promix can screw with the PH level. If I would have know this I would have left the Promix alone and went with just the fox farms soil. I guess I was trying to strech the soil or make it go further by adding the Pro mix to it. I now know for my next grow its going to be just Fox Farm soil and thats it, might also go with their nutrients too.