A yellow algae is a form of green algae that has become resistant to chlorine and other sanitizers. Unlike green algae that floats on top of the water, yellow algae clings to surfaces, such as the walls, bottom of the pool, or on other objects like pool lights, ladders, and filters. If you already have yellow algae in your pool, you will want to shock your pool using a strong algaecide to get rid of the algae. This will kill any bacteria that may be causing the problem. Visit poolchemservice.com to know more.