Okay. You have very likely hard tap water for your numbers to be that high so barring pH lockout, Calcium def is highly unlikely.
However you have created conditions for Ca def by just CRANKING those plants full of thrives. I see in a couple instances use of both in one day. Plus OD with supa-thrive. There's a problem.
Mineral matrix, silica blast, and hard water seems pretty heavy on the minerals. Another possibility.
Last, the PM and mite treatments are another possibility- did you do a sensitivity test prior to use, or raise the lights after application?
I have to defer to rhizome on this one for a proper diagnosis but my hunch is that the combination of weakening your plants with the nitrogen OD from the thrives, and then hitting them with 2 different chemical treatments, would be enough to make them look like that.

Your friend is correct for a soilless flush. That's a good pH to flush that mix with from what I know about soillless (not a lot... lol). I also think you can lay off the silica blast and mineral matrix. Your tap water could stand a spoon on end, lol! Can you get a water sample over to the hydro shop for a quick EC test to confirm?
stinkyattic Reviewed by stinkyattic on . Problems in Soiless My grow is: Indoor,soilless,Sunshine mix #4 and #2. Nutes I have and use consist of: Super thrive 1-1-1 Earth juice grow Silica blast tiger bloom 2-8-4 Rating: 5