amendments causing lockout

Hey coconauts, I think I'm in over my head here. I recently started my second indoor run in coco, and decided to amend this round. Beginning with 15 gallons of re-used coco, I added 8 tablespoons of lime, 6 tablespoons of gypsum, 6 tablespoons of blood meal, 6 tablespoons of azomite,8 quart of earthworm castings (with 1% volcanic rock) and around 6 quarts of perlite.

Anywhom, got the new clones in there and right off the bat they are showing bad cal/mag deficiencies. Leaves are tacoing from the outside in, young and old. I gave them 5ml/gal of calmag, then 7.5 and finally 10-- no avail.

Having had this exact issue with lime in soil before, I assumed it was causing lockout.
I just made a slurry solution 1/4 cup of my coco medium into 1.25cup RO and tested the pH 4 hours later, it came up 6.7.
Is this something that will correct itself with a few waterings of low pH solution? Or did I just potentially waste 15 gallons of medium.

Thanks in advance blades, any help appreciated.

Edit: I understand not everybody re-uses coco, so I should mention that after my last harvest the pots were left outside for several months. I occasionally watered them with a strong solution of pondzyme, occasionally adding (very light) molasses and seaweed extract to break down the roots. This worked quite well, most pots had no trace of roots left, but a few of the bigger root balls left a few roots, <5% remaining in the worst case I would estimate. I doubt this would explain the high pH, but I thought I'd mention everything relevant.