What have you been using?

If it's bromine tablets (BCDMH -- bromo-chloro-dimethyl hydantoin), that may be the source of the problem. BCDMH use leaves high levels of dimethyl hydantoin, a known severe skin irritant, and which also reduces the effectiveness of low levels of bromine.

Is this pool indoors?

Also, why did you title your post "skin rash"? Are you still getting skin irritation problems?