Thin, curled down, and ugly

I am on my first grow, hydro drip system 400w hps bulb 12/12 and using GH one part hydro solution. because of a really bad pH fluctuation and some bad handling (don't ask) I am now down to only 1 of my babies left! Now this one is going too. The leaves were originally very broad and indica looking but now the leaves have turned a lighter green and are curling downward and are extremely thin. This is the 3rd week into flowering and the buds are looking great, but i cannot figure out for the life of me why this is happening. Hopefully I will have a photo by tomorrow. Any ideas on what this could be?