First grow and I'm seeing some discoloration in some of the leaves. Also have weird green stuff on top of some of my 4x4 rock-wool. I am in week 4 of veg growing Sour D. I'm growing in bubble buckets and using GH 3 bottle flora system for nutes. Avg. temp is 74 and avg humidity is 50%. Roots seem to be growing fast and strong. Attached are some pics. Any advice would be greatly appreciated. another pic attached
My guess without seeing a pic us that you have algae growing on top of the rock wool. It's completely normal and it can be prevented by using covers for the blocks. You can make tops using white material that will reflect and block the light from the blocks. Keep in mind that the material you use will be getting wet so something like a plastic cut to size might work best.
I always cover the top of the rockwool with claypellets to avoid this. I don't think it will hurt anything, but it looks nicer
