It sounds like you have something that I've called "sand algae" -- under certain conditions, algae can build tiny calcium domes over itself. When the algae is dead, the scale remains. You can check it this way:

1. Remove the Polaris from the pool.
2. Fill a 3 - 5 gallon bucket with 1/2 gallon of bleach + 1 gallon water.
3. Put a section of hose in the bucket, so the green scale is immersed in the bleach solution. You don't need to remove the hose to do this; just fold a section into a 'U' and put it in. Set something on the hose, to hold it in place for an hour.
4. Remove the hose, and pour the bleach into the pool. Rinse the hose with fresh water and then inspect: if it's sand algae, the scale will remain, but will be tan to brown, instead of green.
5. If it appears to be sand algae, continue to step 6. Otherwise, report what you found here.
6. Rinse the bucket out, and fill it with 1.5 gallons of water. Add 1/2 gallon of muriatic acid. Put the bleached section of the hose in the acid solution; wait 5 minutes. Remove and rinse. The scale should be gone. Pour acid solution into pool.

CAUTIONS:

1. The bleach solution will damage clothes instantly, and eyes quickly: wear old clothes and safety glasses, or at least, sunglasses. Have a hose ALREADY RUNNING a small stream of fresh water, nearby. Rinse spills promptly.

2. Muriatic acid fumes and damages eyes, and can burn skin. You need glasses and gloves (kitchen gloves are fine). Once it's diluted, it will stop fuming. READ THE MURIATIC ACID PAGE, linked in my signature.

NOTE:

1. You need to report pH, alkalinity AND . . . calcium levels. If this is sand algae, you'll need to manage those levels differently.