How to Remove Black Algae In Your Pool Fast

Algae are the simplest form of plants that grow very quickly in and on any moist location. Algae can grow easily on stones and other hard surfaces if it moist for longer periods. Algae are easily found growing near water bodies. Anywhere there is water it is possible there are algae present.

Of all the algae types, the hardest to remove by far is black algae. Black algae are the most resilient type of algae and can quickly grow back if conditions are favorable for it. Spores can enter pool water through various sources like wind, swimming pool equipment, toys, dirty filters, etc.

If black algae are blooming in your pool water, then you should take measures to remove it completely. Follow these steps to rid your pool of any trace and black algae:

  1. Brush the Pool

    If you see black algae present in your pool then brush daily for a week with the proper brush. Pay attention to algae affected areas. It's important to brush first because the protective layer that's present on black algae makes it impossible fluid to pass through it. Hence, without proper brushing, the use of regular sanitizers will be ineffective. Using a brush will break the protective layer. Black algae have deep roots that grow into the walls, grout and the pool filters. These roots need to be destroyed to stop algae from growing back. You can also rub chlorine tablets at the place of algal growth after brushing it properly.
  2. Add Algaecide

    After brushing, add copper-based algaecide. The algaecide should contain 30% active ingredient concentration. Aim the water return jets at the algae affected areas.
  3. Shock the Pool

    After the algaecide is used, shock the pool. At the same time, continue the daily brushing and after three days, shock the pool again.
  4. Vacuum it

    Vacuum the pool to clear dead algae and all the debris that may be settled at the bottom of the pool or floating in the pool water. Adding flocculant will clump the materials together and make it easier to remove.
  5. Clean and properly Sanitize Filters, Equipment and Toys

    Spores of black algae can hide in the filters and they bloom again when the pool water conditions are favorable. Black algae will clog the filtration system and decrease its efficiency.

    Wash all towels and bathing suits and dry them to get rid of any algae that might have attached itself to the fabric. Clean and sanitize all the toys and pool equipment by scrubbing them with a bleach-based cleanser.

  6. Test the Water

    Test the pool water regularly, especially if you have adjusted the chemical levels of the pool.

    Following these steps can successfully remove black algae from pool water. Algae spores are always present in pool water and if conditions are favorable, they will bloom in no time. Conditions that favors and promote algae growth in your pool include poor circulation, poor filtration, a high pH level, and a low chlorine level. Keep a close eye on these issues to prevent black algae from growing in your pool. Timely pool filter cartridge replacement to enable proper filtration of the pool water may also be needed.


Algae is not harmful to humans but its presence in pool water encourages bacterial growth. Presence of algae in your pool water indicates the likelihood of harmful bacteria and other microbes and is unfit for swimming. Dirty pool water can sometimes cause infection and serious illness to swimmers, so keeping an eye out for algae is a great way to prevent it.