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How to Tell If You Have Mustard Algae

By Dawn Roberts ; Updated September 21, 2017
Mustard algae can be a pesky unwanted visitor if it invades your swimming pool.
swimming pool image by apeschi from Fotolia.com

Algae can be the bane of your existence if you are a pool owner and must be dealt with firmly after it is diagnosed. Your pool could have become infected from a variety of sources. Sometimes mustard or yellow algae develops through spores being introduced to the pool from improperly cleaned swimming suits or transmission by air or rain.

Look for debris in the pool that looks like sand or dirt.

Note where the suspected algae is in the pool. Mustard algae is often found in the shady side of the pool.

Determine whether the debris is sand or dirt by attempting to catch some with the pool net. You might have to resort to using a plastic cup to collect some of the material.

Examine the debris closely to determine the color. Mustard algae will have a distinct yellow tint, whereas sand or dirt will be more tan or brown.

Look for cloudiness in the water. This combined with yellow growth signals mustard algae.


Things You Will Need

  • Pool net
  • Plastic cup

About the Author


Dawn Roberts has been writing professionally since 1996. Her stories have appeared online and in print. She has also been heard on various radio stations. She holds a bachelor's degree in journalism from Pennsylvania State University and was awarded the Hearst Award.