Rainfall can be a welcome sight for pool owners, providing a natural way to top up water levels. However, it can also disrupt the carefully balanced chemistry of your swimming pool. Understanding how rain impacts your pool's water is the first step to effectively managing it. NINGBO INNO PHARMCHEM CO.,LTD. provides the chemicals and insights needed to maintain perfect water balance, even after a storm.

How Rain Affects Pool Water:

1. Dilution of Chemicals: Rainwater is essentially de-mineralized and lacks sanitizers. When it mixes with your pool water, it dilutes all your chemicals, including chlorine, pH balancers, and alkalinity adjusters. This dilution can lower chlorine levels, making the water less sanitary and more prone to algae growth.

2. pH Fluctuation: Rainwater is often slightly acidic due to dissolved atmospheric gases like carbon dioxide. This acidity can lower your pool's pH. Low pH can cause eye irritation, corrode pool equipment, and reduce chlorine's effectiveness. Conversely, sometimes rain can pick up pollutants that might slightly raise pH.

3. Introduction of Debris and Contaminants: As rainwater falls, it can pick up dust, pollen, leaves, and other organic matter from the atmosphere and surrounding surfaces. This debris depletes chlorine and can introduce nutrients that feed algae.

4. Overflow and Water Level Changes: Heavy rainfall can cause the pool to overflow, leading to a loss of treated water and further dilution of chemicals. This also affects the efficiency of your skimmer, which is crucial for surface debris removal.

Steps to Restore Balance After Rain:

After a rain event, it's essential to take prompt action to re-balance your pool's chemistry:

  1. Test Your Water: Begin by testing all key parameters: Free Chlorine, Combined Chlorine, pH, Total Alkalinity, Calcium Hardness, and Cyanuric Acid (CYA). Pay close attention to chlorine and pH, as these are most immediately affected by rain.
  2. Adjust pH and Alkalinity: If your pH has dropped, use a pH increaser (like Soda Ash) to bring it back into the ideal range of 7.2-7.6. If alkalinity has also dropped significantly, you may need to add an alkalinity increaser first before adjusting pH.
  3. Restore Chlorine Levels: Due to dilution, your chlorine levels will likely be low. Use a chlorine shock product (calcium hypochlorite or dichlor) to bring the free chlorine level up to the target range. For severe contamination or algae, a higher dose may be necessary.
  4. Replenish CYA if Needed: Heavy rainfall that causes overflow can also dilute CYA levels. If your CYA reading is now below the recommended 30-50 ppm, add Cyanuric Acid to stabilize your chlorine.
  5. Clean and Filter: Remove any debris that has entered the pool using a skimmer or vacuum. Run your pool filter continuously to circulate chemicals and remove any suspended particles.

For pools using DE filters, ensure you replenish the DE after backwashing, as rain can wash it away.

NINGBO INNO PHARMCHEM CO.,LTD. offers a comprehensive range of water treatment chemicals, including pH adjusters, chlorine shock, and Cyanuric Acid, to help you quickly restore your pool's chemical balance after rainfall. By staying prepared and testing regularly, you can ensure your pool remains a clear, safe, and enjoyable sanctuary.