you know i wish i could give you a real answer but all i have is a guess. is there any other water you can give it? that is a strange brand of water and if you dont know the ph then i would imagine that is your problem. the rest soulds close to ideal. it looks small for what you got going on. if that water is the problem then it would make sence that it has slowd growth from the get go. . .i dont know much as i am on my 1st grow still. im sure someone will come along with what you are looking for.

i had this problem as well but when i started i was not expexting to get too deep in to it so i didnt ph my water. i just filterd, meashured and fed it to em...along the way after introduceing nutes the lower leafs starting to dry, curl, brown, and get crispy..finaly after fine tuneing the water with the exact amount of nutes and adjusting the ph did this go away..so there is some hope. you will find a real answer soon