i use PBP and have used fox farms powders. thats my recipe, but i just got a freebie of hydroplex, its botanicares p-k booster, its a 0-10-6. what i like about it is it has the gaurenteed analysys of all the micros like molybdenum etc. one thing about any PK boosters is start slow with them, use your standard bloom ferts as normal and go slow, if a bloom boster at 1/2 strength jacks up your ppm then start at 1/4 like you would do at the early stages of a plants life. my main reason for the use of fox farms Beasties(0-50-30) and Cha ching is (9-45-19) is even at 1/4 strength they are plenty potent to make a difference, so a little goes a long way, but more importantly you can use these as stand alone fertilizers, they have plenty of micronutrients, you can get away with using cal-mag and these powders straight up for middle-late flowering