Any type of algae infestation in a swimming pool can be a challenge for a pool owner, but yellow algae is even more complicated than the standard green variety. Yellow algae, also dubbed mustard algae due to its yellowish brown hue, is much more stubborn than its green counterpart. While this algae will respond to the standard algae treatment, it might not be enough to get rid of this infestation once and for all. You need to bring out the heavy guns and show plenty of perseverance if you want to truly rid your pool of yellow algae