Thread here on it, I have only used them once to try and adjust ph levels in soil. Acid vs Alkalinity..
Seems some have input on it in that thread..
Personally I have had issues in the past trying to keep an even Ph level in soils, so tend to stick with same brand soil/nutes and go easy on "trying" new things... Nothing worse than watching your plants turn yellow mid grow...
Still get good bud out of it, but definitely affects it overall in the end.