Have you tried flushing? Im using coco and i know it holds salts more than any other media, but ive flushed mine several times and mine are still way to dark and clawing.
Yes, I'm flushed on the daily. I'm in coco as well and am feeding in the morning, then just watering in the evening. DTW with 1 liter each time.
Honestly think its the feed program. Here is my regiment:
Veg: GH MaxiGrow, then alternate between Floralicious and Liquid Kharma.
Bloom: Emerald Harvest Cali Pro 2 part + their Emerald Goddess, Honey Chome, King Kola.
Common: Armor Si, CaliMagic and Great White. pH'd to 6.3-6.5
We'll see how the transition to bloom feed goes. The humidity has been on the lower side lately now that I have a lot less transpiration in my room, which may also be a contributing factor.