Not all pool algae is created equal. There are three main types of algae that are found in swimming pools: green, mustard and black. Green pool algae is the most common type and the easiest to treat and prevent. Green algae usually floats freely and may result in green-looking pool water. 

Mustard pool algae clings to your pool surfaces and may resemble yellow or brown dust or slime. This tough to treat algae can reoccur and is resistant to chlorine. Black pool algae are the most stubborn. Black algae attach firmly to pool surfaces and form a protective crust. 

Identifying your type of pool algae is the first step to curing your algae woes for good. Follow these steps to treat and prevent all types of pool algae.


Test and Balance Water

Always begin by testing your pool water. Your test results will tell you if your water parameters are unbalanced. Pay special attention to your Free Chlorine level. Low Free Chlorine can cause algae to grow in your pool water. Always maintain Free Chlorine between 1 -4 ppm. If needed, apply the appropriate chlorine and sanitizers to restore adequate sanitizer levels.


Clean Pool Water and Surfaces

Skim water surface to remove visible debris, brush walls, vacuum and empty skimmer baskets to clean pool surfaces. Concentrate on areas with visible algae and little or no circulation. Cleaning your pool regularly is an effective step to prevent algae growth.


Apply a Shock Treatment

Crystal clear water starts by applying a pool shock. Shocking your pool water helps to remove contaminants that may cause algae to grow and helps to improve water filtration.


Apply an Algaecide

Select an algaecide specially formulated to treat your type of pool algae. After treatment, some dead algae may remain in your pool. Continue to thoroughly brush your pool’s surfaces often.


Clean Filter

Backwash or chemically clean your filter, according to your owner’s manual, to remove dead algae, organic contaminants and mineral build up. Allow your pump and filter to run continuously for 24 hours so that your pool’s entire gallonage has the chance to run through your clean filter.

For best results, test and balance your pool water weekly. Download the Clorox® Pool app for expert water analysis and product and dosage recommendations. If your algae persists, contact us to help further troubleshoot.