RQS Milky Way F1 - Auto (70x140)

Noticed some spots on just one plant (middle) on one cola. The next day the spot spread on the same cola, and another day later I noticed a few more spots on a couple of other colas and some of the fan leaves on that same plant are not looking very healthy. I think I am dealing with salt buildup and nutrient lockout right now, EC runoff was over 3.0 and PH was at 7. Regular feeding is at about 2.0-2.2 EC, 1.7-1.9 being nutrients I have been flushing the plants over the last couple of days with about 40% of my regular nutrient solution (1.0 EC - 0.65ec being nutrients) until the runoff was about 2.0EC and the PH around 6.8. But the next morning my runoff was back in the 2.8-3.0EC range.. I plan on watering quite heavy with runoff using the 1.0EC solution until the runoff is consistently below 1.8EC for multiple days in a row - so far I do not think the issue is spreading...