WTF, dude, runoff pH 5.8 would KILL your seedlings in a soil grow. I've already brought up your bad advice...

It's just the FFOF being too harsh as was mentioned earlier.

You can flush it slightly with plain tap water, and pH in fresh soil is not going to be a problem in almost ANY case. Plants usually grow out of overfert that they suffered as seedlings if you catch it in time, and those should be okay.
In a few days, I would give just the LIGHTEST foliar feed of 1/4 strength complete grow fert with micronutes to try and green-up the plants until they do get around to growing out of the sensitivity. I think they will all survive if you flush some of that fert out of there.