Unless your pH is ridiculously alkaline or acidic, the microbes will be fine. They’re soil microbes, not water microbes. Don’t leave them in water. Mix and use right away. The small volume used of Recharge solution is not going to change the pH of your media.

NEVER post pictures of just leaves. There is no context. We need to see the plant and where the issue is on the plant. Random damaged leaves say nothing.

The high nitrogen ratio in veg is less acidic than the high phosphate ratio in flower. Plant available phosphate (H2PO4) is only a little less acidic than the pH down phosphoric acid (H3PO4) you’re using.

pH is the issue. Measuring pH could be another issue. Digital meters lose their ability to give accurate readings over time as the neutral reference probe that contains potassium chloride will leach out giving false readings. I always suggest having pH drops as an analog way of checking pH. Get the pH down to 5.5 and you’ll be good.