Fox Farms is DEFINETLY for soil, they have a hydro version of there grow formula but the original big bud and grow big are for soil. I think fox farms is borring personally, really the pura vida nutes are the shit for a base nute, they have a high consentrate I have had nothing but good results from it, Yellowing leafs can be anything, but just make sure not to overwater your plants, stick ur finger in the soil and if its even alittle wet wait a day, this in turn will get rid of the gnat problem I am assuming your probly have, also never over do it on the nutes, I always start with 1/4th streght of all my nute mixes then gradually go up in power, if i see something different after a watering i back off alittle. let me know if you got more questions.. +reps never hurts ha
thank you for posting on my thread. however i checked the labels on the foxfarm nutes and is printed clearly specifically designed for hydroponic systems. so i'mm leaning towards a lighting issue. i'm using 2 400w hps and 1 1000w mh the three lights are in seperate dome reflectors air cooled i keep the hps around 15" off the plants higher on the mh. i went to a sheet metal shop to have a reflextor made to hold all three lights in a 4x4 reflecter the size of my pan. i am using a lower nute solution some of my leaves were starting to yellow. any other advice is greatly apprieciated.