SponGieanswered grow question 6 years ago Hi man :) i see your problem, this would be calmag deficiency from my point of view.. you are giving them RO water that has no minerals or nutrients whatsoever inside it.. when you use tap water the tap water allready contains some nutrients like calcium and magnesium that why when using RO water + LED's like you are, its better to add more calmag then usual (not too much or you will have problems aswell) when we grow we learn the plants and their needs, next the PH of your water, try to go with 6.5 in soil if its possible for you, if you need anything let me know