Royal dwarf 1st grow

I am still having a cal mag problem. I think I may have nutrient locked the plant. I am not going to use RO water anymore because I think it’s part of my issue. I did not change the water but added 4 gallons of filtered tap water. I added 15ml cal mag and no other nutrients. Brought my PH up to 6.4 800 ppm going to try to flush it out a bit and see if it improves. I trimmed up some of the leaves dying leaves at the bottom and some crusty ones on the top. Thinking I only have another 3 weeks till harvest. Hopefully I can make it.