Pool Surface Problems - Staining

There are four common causes of staining:

Minerals in the water
Algae
Microorganisms growing on the reverse side of the liner
Organic debris left on pool surface for extended period of time.

You will need to determine what is causing the stain in order to treat it accordingly. First, determine if it is a mineral stain by placing 1/2 - 1 lb. of SUN pH Minus in a white sock. Shut off the filter and drop sock onto the stain. If, within 5 minutes, you notice a change in the stained area, most likely the stain is due to minerals in the water. However, you should bring a water sample to your professional SUN® dealer for complete analysis. If the stain does not respond to the "sock test," it is likely to be caused by algae, growth on the reverse side of the liner, or unfortunately, there is no effective treatment for growth on the reverse side. See Algae Problems for info on algae treatment.

PROBLEM: Brown stains

POSSIBLE CAUSES: Presence of iron and other minerals or presence of black algae.

SOLUTION: For the removal of metallic stains, use SUN Stain Remover according to label directions. Be sure to follow up with a full dose of SUN Scale & Metal Control II according to label directions to prevent the return of stains.

For gunite pools (DO NOT DO THIS ON VINYL OR FIBERGLASS SURFACES): Shut off the filter. Brush the affected area with stainless steel brush. Sprinkle SUN Black Algae Treatment over the discoloration and allow granules to sink to the bottom directly onto algae to produce a high chlorine level on affected area. See label for more complete instructions. Use brush to help remove discoloration. Add SUN Algi-Crush™ to help prevent future recurrences.

For vinyl or fiberglass pools, follow treatment as indicated in Algae Treatment section for Black Algae.

Once your stains have cleared up, vacuum and backwash the filter to remove any remaining waste. Don’t forget to resume normal pH and Free Chlorine levels.

PROBLEM: Purple stains

POSSIBLE CAUSES: Presence of manganese.

SOLUTION: For the removal of metallic stains, use SUN Stain Remover according to label directions. Be sure to follow up with a ful dose of SUN Scale & Metal Control II according to label directions to prevent the return of stains.

PROBLEM: Pink stains

POSSIBLE CAUSES: Usually due to the presence of a type of bacterial slime

SOLUTION: Follow the instructions provided in the algae section.

PROBLEM: Yellow stains

POSSIBLE CAUSES: Presence of iron