Removing Fungus From a Vinyl Pool

Turn on the filter. Test the water with pool-testing strips. The strips determine chlorine, pH and alkalinity levels in your water with color-coded indicators. Most pools with an outbreak of fungi will have lower-than-recommended levels of chlorine in the water.

Balance your water chemistry. If other aspects of your water chemistry such as alkalinity and pH are not in their correct ranges, balance these chemicals first using chemicals to either increase or decrease these factors. The amount you use will vary depending on current pH and alkalinity levels and the water capacity of your pool. Refer to the manufacturer's instructions for dosage information relative to your pool.

Add 1 pound of diluted granular shock to the surface of the swimming pool water for every 12,000 gallons of water you have. For example if your pool has 6,000 gallons, you will only need to use half a normal, 1-pound bag of granular shock. If you prefer liquid shock, use 1 gallon to treat up to 10,000 gallons of water.

Run the filter continuously for 24 hours. Retest the water to ensure the chlorine level has been raised.