Im not too sure about that since I really havent had that problem, do you have any full plant pics?well my leaves are changing color also, along with all the leaves curling down, they seem small also, and alot of red branches, i think i have some root rot, i looked at the roots and a patch was dark colored, there is also a new set of bright white roots, i read to try some peroxide, so i put a cap full in my reseviour, please give me input, i am in the 4th week of flower.