Ghoster

What will I need to do to get my Alkalinity up? and what other elements will it effect?

Hi all, I have bought and installed a new 15' x 48" pool for my family. I also purchased a salt water system for it. I am having issues with the chemical levels and do not want to let anyone into it cause I don't know what the effects will be on them. My lvls are as follows. Sodium Chloride = 4450 ppm Free Chlorine = ~4 ppm pH = 7.2 Total Alkalinity = 40 ppm Is it safe to swim in, and what do I need to do to get the lvls in the recommended ranges? Thanks in advance for your help G