How to Treat Pink Slime (Pink Algae) in Pools

Pink Slime (Pink Algae) in Your Pool

Objective

This guide helps you properly identify pink slime in your swimming pool and provides the exact chemical and physical treatment required to completely eradicate this persistent bacterial growth.

The Truth About the Pink Stain

It is commonly referred to in the industry as "pink algae," but that slippery, pink or reddish substance growing around your skimmer, return jets, or pool lights isn't a plant at all—it is an airborne bacteria (often Methylobacterium).

Because it isn't an algae, standard copper-based algaecides are largely ineffective against it. Pink slime thrives in PVC pipes and dark crevices, forming a thick, gelatinous protective biofilm that shields the core bacteria from normal chlorine levels. To get rid of it permanently, we have to physically break that slime layer and chemically flush the plumbing lines where it hides.

Prerequisites

  • A nylon pool brush.

  • Liquid chlorine or granular pool shock.

  • A strong surface-active algaecide/bactericide (like Swamp Treat™ or a dedicated pink treatment).

Step-by-Step Instructions: Eradicating Pink Slime

  1. Expose the Hiding Spots: Turn the Pump Switch to the OFF position. Carefully unscrew and pull your pool light fixtures out of their niches (resting them on the pool deck), as pink slime famously breeds behind the lights.

  2. Break the Biofilm: Vigorously brush all visible pink spots in the pool, inside the skimmer housing, and inside the light niches. You must break the slime layer to expose the bacteria to the chemicals.

  3. Apply the Treatment: Turn the Pump Switch back to ON. Add your chosen bacterial treatment (like Swamp Treat™) directly to the water. To ensure it gets into the plumbing, pour a small amount directly into the skimmer basket.

  4. Superchlorinate: Immediately broadcast a heavy dose of chlorine shock across the pool. The accelerator chemical will weaken the cell walls, allowing the massive dose of chlorine to instantly kill the bacteria.

  5. Continuous Circulation: Let your pump run continuously for 24 hours to ensure the highly chlorinated water flushes completely through the underground pipes and the filter media, destroying any hidden spores.

Troubleshooting Note: Don't Forget the Toys!

Because pink slime is highly transmissible, it can easily survive on wet pool noodles, floats, and automatic vacuum hoses. Throw all your pool equipment and plastic toys into the shallow end of the pool during the superchlorination phase so they are sanitized along with the water.


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