Mid flower problem please help

Alright, first off I recommend getting a decent ph meter (amazon around 45$). Then you need to be measuring your runoff ph, this will give you an idea of what your root zone is at, and you can make adjustments to your feed ph if the rootzone ph needs adjusting. As far as feeding, the only thing I feed my plants is ghe maxibloom and calmag. I feed every other watering, I use .75tsp of maxibloom per gallon, and 1tsp per gallon of calmag. I've haven't seen a single issue with deficiency or excess using this schedule, I keep my ph around 5.8-6.1 and the plants are good with it. Happy growing.