I'm using the FF 3 part set in my grow (see KGB/Lemon Skunk thread in Grow Logs ) using coco as a medium. I use 1 tsp of Grow Big (soil version)or Tiger Bloom depending on where the schedule is, and 1 tbs of Big Bloom per gallon of water, feeding once every day, with a clear water flush on Sunday. Seems to be working remarkably well so far. Not using the solubles, though.

Quite correct about the FF line lowering pH, my well water is quite hard (8.0 or higher). Adding normal amount of nutes brings it to around 6.9-7.2 range.