Fox Farms makes 2 versions of Grow Big, one for hydroponics, one for soil ... their nutrient ratios are quite different, but no harm done with the 'older' soil ratio ... as to their pH, etc.,, I didn't even check it out of the bottle, they may differ, also ... and, by coincidence, I switched to Fox Farm about the time I was running low on GH nutes, and they did get mixed in an early grow ... no probs that I saw ... BUT, although the GH nutes are significantly 'cleaner' than the Fox Farms, I grew the best plants of my life using only Fox Farms products ... and, since I was fairly new to hydroponics, I really liked how easy they were to use ... I pretty much used the dosages Fox Farms recommended on their chart, and had no problems at all (can be seen on their website, as well as brochures) ... obviously, I'm a Fox Farm Fan (FFF,WTF) :wtf: ...