Honestly if you’re in soil and using some kind of microbial inoculant (recharge, Mikrobs, mammoth p, great white etc) anything between 5.5 and 7.5 should work fine. Only reason I even bother adjusting ph is my use of silica which bring my ph up to like 9.5, toss in a ml of ph down and it’s back to like 6.2 then I add the calmag and the fertilizer