chlorine level question

I live in deep south Texas and the weather here has been very hot. My question is what level should my
pool's chlorine be during the day. The temprature here has been in the high 90s to 103 F. i've got an intex
ultra frame 22' x 52" with an intex salt water system. The chlorine during the evening hours is at 2 ppm but
during the day It seems to evaporate fast. The alk is at 85 and the ph is at 7.5, cya at 60 ppm.

Thanks in advance..

The Best Guess chart (link in my signature) explains what your chlorine levels should be, day and night.