So i know you said the meter is calibrated, but meters need to be re calibrated often. Dude when you lower your ph your plants gonna die. Your gonna over feed it for sure. I was wondering why you were not over feeding it right now, but thats because your ph is to high and your in lockout. Shits slowly gonna go south on you from here with that ph, and even if you lower it.
Most people put to much stuff in their res. You need some people familiar with your nutrients to tell you what not to add. There is no way those plants need all that right now. I dont even add my bloom booster until they are flowering. Again, not trying to be rude but if you do what we say and lower your ph, lol. . .i think ur plants gonna die fast. Perhaps turn your light down a bit to slow this thing down. The last thing you want to do is make a plant grow faster when it has issues. But I guarantee you that your ratios are incorrect. And. . when you correct them, im afraid that your Tap water is way to high. So go study youtube under sink ro systems and yea. .
Not trying to be a downer, but I just dont see how youve gotten this far. Ph just started rising on ya and now you cant keep it in check.
So you can always add a ph buffer. So blast the ph up to 10, then bring it all the way back down to 5.5. Its not really alkalinity but its a buffer.