Swimming pools blog

Dear Group,
I have an algae problem in an in ground vinyl liner pool that is not
getting any better because the combined chlorine is so high with little
free chlorine.
I have shocked it with both sodium hypochlorite liquid, calcium
hypochlorit, and potassium persulfate to release the chlorine, but none
of them seem to work.
Any suggestions would be greatly appreciated.
Thanks,
Todd Kroehle