What soil are you using and have you calibrated your pH meter recently? (cuz I suspect the pH you think you're using is not what it actually is, jmo)
You can put a tablespoon of Epsom salts in a gallon of water and spray those leaves because they need magnesium but you've got to figure out what you're screwing up with your pH that's causing the issues in the first place?
I use only Apera meters, they start about $45 on Amazon, they're the best investment I've made, and I suspect proper pH would end your issues as well, Best of luck!