Black algae in vinyl pool appear as a couple of small black spots on the pool liner. They are rugged organisms with a chlorine-resistant coating.
How to Get Rid Of Black Algae In Vinyl Pool
- First, brush the algae spots using a nylon brush (BUY ON AMAZON) to open up the algae coating.
- Test the water PH levels and reduce it to the lower limit of the normal operating range (7.2) to improve the chlorine effectiveness.
- Next, superchlorinate the pool and add a dose of quaternary (‘quat”) type algaecide (BUY ON AMAZON). Ensure you follow the recommended dosage from the manufacturer, as too much use may cause foaming.
- Continue to brush the algae stains to increase the chemical penetration which results in better efficiency.
- Last, vacuum the dead algae to the drain once they have been killed.
Once its been two days after superchlorination, add a dose of Polyquat (polymer algaecide) as per instruction on the product. Polyquat are more expensive than typical quaternary algaecides but they’re better at controlling these resistant algae types.
Now that the staining has been taken care of, resume normal chlorination and water balance.
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Note: The best protection against algae growth is a constantly held free chlorine level in the range of 1-3 ppm, a total alkalinity between 80 to 120 ppm, a PH between 7.2 to 7.6, and a calcium hardness of 200 to 300 ppm.
Another type of black/gray colored stain can happen when dye-producing microorganisms colonize the vinyl liner back side. To solve this, do some superchlorination and put a polyethylene barrier between the vinyl liner and the walls and floor of the pool provide a barrier to these types or organisms.