ill copy and paste this from another site that has people growing with led thats have the same problem as me, its just a case of plant under led needs more of these nuts or the leaves burn away
"I have been trying to trouble shoot a problem with my plants under my BS 600 Led's recently. So I was doing some reading up on nutrients from my Growers Bible and found that "chelates decompose rapidly in any low level of ultra violet light including light produced by HID bulbs and sunlight." I have noticed people using Led's have a wide range of issues when they get the light to close. General Hydroponics floranova has chelated iron, manganese, and Zinc. The nutrient line I am using has Chelated Calcium. Dutch master uses chelated Iron, etc.... I have found BS users having issues when they try to get the light 14 inches during flower when their usually is a lot of growth I think it might be the chelated Iron that I have seen any many of products. I have added some Calcium and iron to my feeding and it seems to be bringing some burned babies back to life."
and
"it will help if you use AN's "Revive" on a regular basis. Cal-mag also will help with the issues your describing. I was looking at my nute mix and found that there is alot of calcium, magnesium and iron in my mix. I dont have any issues with bleaching after my first round with their lights. I just started adding "Revive" at every feeding."
they have the very same problem i have and yeah its the white bottle with a plant and a red cross on it, 20 euro for 1 liter