FFOF used to be good stuff, as Surf’d pointed out they’re having some quality control issues, I used to use FFOF with extra perlite and nothing else, and it grew beautiful plants, if you’re not having problems with it would it use it as is. Best thing to do is get a good Ph reading of the soil first, if the soil is with a range of 6.3 to 6.8 and you’re still having issues, quit using the soil I doubt buffering the soil will help. If the soil is below 6.3 add dolomite at the rate of one cup per cubic foot of soil let it set for a few days and measure the soil’s Ph again, if it’s with 6.3-6.8 you should be golden, I’ve never used too much dolomite so I really don’t know, honestly if you have to use more than 1 cup per cubic foot, I really wouldn’t use the soil