I am not sure how to fix this issue. I seem to have a dark green moss growing in some spots along my pool. Specifically, there is some in the grout along the water line. I did find moss on one if the steps a few months back but I thought I corrected it by upping my chlorine levels for a while. I'm in Phoenix so I have very little experience with moss in an otherwise dry environment. The pool is salt water. The moss spots are very small and I wouldn't have even noticed them if I wasn't right up against the wall looking at them yesterday. I can post more specific water chemistry a little later today but my chlorine, salt, and CYA are in a "good" range, alkalinity and pH are high. Does anyone have experience with this?