Sunblock and sunscreen combine with the chemicals in your pool water to cause a reaction that’s actually visible in and on top of the water.

HTH Can sunblock cause cloudy water image

The chemical imbalance between sunscreen/sunblock and pool water can cause:

  • Cloudy water
  • A scummy gray layer on top of the water
  • Skin or eye irritation
  • A rainbow-colored oily layer on top of the water

Of course, the use of sunscreen and sunblock is very important – we have to protect our skin in the sun. That’s why we’ll cover the best solutions for this summer-long challenge.

Solution 1: Check the Filter

Check to make sure your sand, cartridge or D.E. filter is working properly; remember to backwash or clean it regularly. Take a look at the pressure gauge on the filter; this is a good indicator for how dirty the filter is.  When the p.s.i. on the gauge increases by 10 p.s.i. above the normal clean pressure, you’ll know it’s time to backwash (sand & D.E.) or rinse off (cartridge) the filters.  Make this filter check part of your weekly pool routine. In addition, it’s a good idea to periodically use a filter cleaner solution on the filters to remove stubborn oils and embedded lotions. 

Solution #2: Apply Scum Remover

Did you know you can prepare your pool water to handle sunscreen? This is an important maintenance step for keeping your pool water healthy and sparkling across the summer. Add a scum remover to your swimming pool BEFORE swimmers enter the pool. If you wait until after the water is already cloudy, your pool will take longer to clear up. In some cases, black residue builds up in your pool filter, skimmer and hardware, and it can be difficult to remove. The enzymes in scum-removing solutions digest oils, lotions and other organic materials, breaking them down naturally. Scum removers can eliminate scum lines and prevent them from coming back, and a select few will also protect against oily buildup in your pool’s filter to help ensure it’s working efficiently.

To remove existing scum lines, be sure to check the label for proper dosage of your pool size. With HTH® Scum Remover, you’ll add 16 oz. of solution for every 10,000 gallons of pool water until scum lines dissolve. For prevention, add 8 oz. weekly for every 10,000 gallons of water; this will prevent oils, lotions and other organics from accumulating on walls, in the water or in your filter.   

Solution 3: Add Shock & Scrub Walls

Scrub the backsplash around the water line with a soft, abrasive sponge. If you still notice scum or other build-up, add a cal-hypo shock treatment like HTH® Super Shock! in the evening. You can swim again when the free chlorine levels are between 1 and 4 ppm.

Solution 4: Swimmer Management

Don’t be afraid to put some parameters around sunscreen application. Suggest swimmers apply sunscreen 25-30 minutes before they get in the pool. That will help avoid shedding extra sunblock into the water. If swimmers use water-resistant sunscreen, ask them to shower before jumping into the pool to rinse off any excess lotion or spray.

As always, HTH® is here to help. If you have more questions, you can call our HTH® Help Line at 1-866-HTH-POOL.