thats because FFOF is hot
needs to be mixed with something else like light warrior or a media that has excellent drainage without a nutrient charge. that mix will keep you good for a month. plants will tell you when they need more fertz. then start feeding at 1/2 strength and work up.
dude epsom salts work weel in a foliar treatment but only really for mag, not the cal. Calcium is immoble and has to be taken in from the roots. It takes a while to restore the plants new growth to a clean apperance and rid the cal deficiencie. Chances are that you had enough cal, it was a PH imbalance that threw your plants into a deficiencie. And excess mg is not good either, especcially foliar fed because of its almost immediate availability.
I knew the FFOF was hot when I chose it. I had gone with the promoted mindset that I could pop them in pure FFOF and they'd be fine, but the fact is the person who suggested this idea wasn't aware that the strain I was dealing with specifically states "not for rookies" on the guide and is a very sensitive sativa dom. Been aware that cutting it with Perlite/Light warrior would've prevented it but I had hoped they would ride it out, and it seems like with my help they have.
I was told to add more cal-mag from seed due to many LED users requiring cal-mag specifically due to LED. My PH is meticulously checked, rechecked, and adjusted with a digital Hannah instruments pH meter. It has remained a very consistent 6.4 - 6.6. I'm also sure they gained their deficiency from the two Clearex flushes that I performed on them within a short period of 8 weeks (saved the plants but reset the soil). I waited to see nute burn dissipate before giving them nutes after the flush but waited too long and should have had the cal-mag ready faster (had a delay in obtaining it).
Nevertheless, a completely new soil will be used next time, perhaps a super soil I prepare myself.