The first key to algae control in your pool water is recognizing which type of algae you are dealing with. There are primarily three types of pool water algae – green, mustard, and black.
Green algae make the pool water pale green and too cloudy to see to the bottom of the pool. Such algae rarely develops when the free chlorine concentration is above 1 ppm. To prevent green algae from forming, simply brush your pool walls on a weekly basis, adjust the chlorine to maintain the 1 ppm minimum, and regularly use algaecide pool chemicals.
Mustard algae tend to have more of a yellowish tint to it. It appears as a powdery substance on the pool water surface and can spread quickly if gone untreated. Unlike green algae, mustard algae can form even when a pool is being maintained well. Mustard algae is relatively easy to get rid of with reoccurring algaecide, but its cells can continue to grow in small amounts of any of it is allowed to continue to grown on the walls. Because of this, daily wall brushing should be done for two weeks after treating mustard algae.
The rarest form of pool water algae is black algae. Like the other two forms, repeated chlorine doses and algaecide treat black algae effectively. Similar to mustard algae, it can come back quickly if not fully treated. If black algae or any of the other types consistently form, take some or all of the following steps:
- Adjust the pH to 7.2 to 7.4 – algae grows slower in the pH is low.
- Regularly and vigorously brush pool walls.
- Test chlorine and adjust the concentration to 1-3 ppm.
- Shock the pool – 2 lbs per 10,000 gallons
- Add more algaecide – about 24 oz. per 10,000 gallons
- Run the pool filter uninterrupted for up to 48 hours while brushing as often as possible