RQS Fem induction (2 strain indoor)

Some fan leaves turned yellow this week. I believe it is a deficiency as they have been watered with just 6 pH water between feeds and its unlikely to be efficiency. It looks like that it is a mag deficiency as appears in the picture. Biogrow which is biobizz's product with highest % of Mag wasn't used last 2 weeks and I think that might be what caused the deficiency. Overall Green Gelatos are getting dense and smell sweet herbal, 2 short Hulkberries flowering up good as well but the tall one which is the one stretched more takes her time. Hulkberries aroma is a bit gassy but weaker than gelatos at the moment.