Hydro: Root problems?

Classic ebb and flow
res (7 gal) in a 2x2 grow space
4x4 rockwool cubes (4 plants)
3 weeks in flower
Dyna-gro nutes

So this grow has been giving me problems from day one. Overwatered almost the whole veg cycle (5 weeks from seed). Usually I don't worry about it too much because the plants always usually grow into the rockwool with no problems at flower. Since flip though these never really went into overdrive. Allthough only watering once a day the cubes remained pretty heavy between waterings. Some slight wilting problems a few day during the first week or too of flower and then everything started looking better but not great. Now at the end of week three of flower (from flip) I'm noticing some wilting and curling in spots on the various plants. I'm currently running a mechanical timer so I have to water minimum once a day as I am not around usually to monitor the plants and I'm afraid if I don't water a full day the cubes will dry out too much. Now I'm thinking I might be dealing with some minor root rot. What can I do to prevent this from getting any worse? Anything? Or just ride this out and hope for the best? Can I ad a bit of hydrogen peroxide to the res to slow things down? if so how much? heres a few pics for review.

Edit: I'm also having some unusual PH drops nothing serious but something I usually don't have to deal with. This is whats leading me to thinking I have some root issues.

There's a good article on pool shock here
I dont grow in rockwool and I don't put cuts in it anymore I use coco plugs, sorry can't be of anymore help hopefully that link helps.

The problem is after the stretch the roots don't grow a whole lot. I have bonsai mother's in 4' cubes, and if they get too big they will dry out if I'm only watering once a day. Sometimes it doesn't seem to be an issue, but later root problems start to show up.

For my other plants I run 4x4 cubes with rockwool chunks in between the plants so there's a little more medium, but I water my flowering plants once an hour while the lights are on. Anything less I start to see issues. I used to run slabs and could get away with only watering them once a day.