I think that FF is peat-based. Other users of the stuff can chime in if I'm mistaken. If that is in fact the case, you want to drop your pH down to 6.0.my ph is 6.86 using a ph meter
For soil, 6.0-7.0 (6.5 ideal). For peat (soil-less), 5.5-6.5 (6.0 ideal).