Yellow leaves appearing

Flushing.. don't drown it... if yo mean a irrigation of ph'd water only, sure... normal amount wiht a little runoff to ensure full saturation. pic 4 - look under leaves with a scope and look for bugs... if you see none, all good there. problems are mostly on lower leaves, which if nutrient related is mobile... can eliminate possibilities. Could also just be shaded leaves the plant is shedding. pic3 makes me think watering habits. But again, could be simple balance issue with nutes too. If you don't calculate ppm of what you feed, this is simply a blind guess based on most recent behaviour. KNowing what you feed allows you to eliminate more possibiities... Between checking pH is proper, a good wet dry watering habits, and ppms of what you feed, the answer should be very obvious once you investigate these things.. if you aren't following some of these best practices, start doing so and problems may clear up on their own. i'd stick to normal watering cycle (unless you weren't allowing it to dry between or not getting any runoff)... next fertilization, mix it with ~10% less nutes. ensure 10% runoff... see how it goes.