When you say "I've tried everything", exactly WHAT have you tried? Details please. At a minimum, we need to know...
  • Size of pool (either gallons or width/depth/shape)
  • RECENT test results (like from today) for:
Chlorine (total chlorine, free chlorine and combined chlorine) (assuming you're using chlorine)
Alkalinity
pH
CYA (cyanuric acid/stabilizer/conditioner)
Calcium

  • What EXACTLY have you added to the pool, and when (such as algecide, floc, clarifies, etc.-brands and amounts, and anything the "pool store" might have told you.)
  • What type of filter do you have (sand, DE, cartridge)?
  • How long do you run your filter each day?
I'm sure I'm leaving something important out, but someone will correct me.