Organic matter such as pollen, leaves and seeds often fall into a swimming pool. If left alone, pollen will settle onto the sides and bottom of the pool, especially in areas where your pool sweep can't reach. It turns the water a yellow-green colour. If it decomposes in the swimming pool, it will stain the pool walls. Pool chemicals can't remove pollen from swimming pools, but getting rid of it takes minimal effort.
Turn on the pool filter and let it run continuously until the water becomes clear again.
Brush the walls of the pool while the filter is running. Loosen the pollen that settle on the side and bottom walls of the pool, focusing on the corners, where they accumulate. The pollen will become suspended in the water so the filter can remove them.
Test the pool water's chemical levels with a test kit. When pollen falls into the pool, the chlorine in the water breaks it down. This process depletes chlorine if a lot of pollen enters the swimming pool. As such, the chlorine level in to pool might not be enough to resist contamination from algae spores and bacteria that enter the pool water with pollen.
Add granular or liquid acid to the pool water to decrease the pH or add soda ash to increase the pH. A pH level from 7.2 to 7.8 allows chlorine to work effectively.
Add enough chlorine to bring the level to 2 to 4 parts per million. This gives the pool water more resistance against contamination.