2 Tsp of CalMag both feed and water? You're giving twice the nitrogen that's in the Green Gro bottle every couple of days. Tap or RO for water?
Personally, I'd flush with Tap until runoff was good and back off the CalMag to 1 Tsp, unless there's a reason to use that much. It sounds like you have salt buildup, to me. It is hard to tell without seeing the plants.
Good luck with the grow!