I have a way less severe form of what you have in the first pic, burnt tips. I'm in week 6 of flower, and have been mixing about 1250 ppm nute water, only to watch my water drop by half a gallon 24 hrs later and ppm jump to 14-1500. So tonight I decided to do a 24 hr water only flush (hydro guard and cal-mag since using RO water) and going to remix nutes at 900. Just gotta read the plants if she drops in ec then I'm good. But I think you would benefit from a quick 24 hr flush.
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