Flushed them with 6.5 water and tested pH & EC of runoff. It wasn't lockout, there were no nutrients in the soil. The nutrients I had been using were worthless. Even brewing expired organic nutes into a tea couldn't save them.
Once I found this out, I followed the the flush with a heavy slug of salts as a bailout. Will use the salt nutes for the rest of the grow; I think that's how I bring this one in home.