I personally would not recommend ffof when running a full liquid nutrient schedule. Promix, sunshine #4, perlite, peat moss, whatever combo you like. Your not getting from you medium with these, so it's a different approach than true organic, but it seems like psuedo-hydro is what your trying to do. I've not heard of anyone successfully growing treating FFOF, like a soilless medium, but it seems like 50% of folk still try it. Best of luck. I hate to not give you complete info, so your previous grows I would not chalk up to "lock out" or a bum batch of Fox Farm, most likely it was a combo of over saturated medium which goes hand in hand with salt build up, PH inbalance, and therefore nutrient lock out. There is also much more chemistry involved in a complete answer, but basically, reactions take place between the organic compounds in your soil and your liquid fertilizer that can render certain minerals unavailable.
