ur good then. 6.5 to 6.8 is good. keep checking it tho cuz ffof tends to drop and raise its ph. a lot of people have problems with it being too low (acidic) but i had problems with it bein to alkaline. had to flush it real good to drop it back down.
how r u checking ur soil ph? wanna make sure ur doing it correctly
6.8 PH is ideal for soil. But as was asked, how are you checking your PH? Depending on where you are at with your grow, you should really be using Grow Big and Big Bloom as well with your grow.