Recurring algae can be a problem this time of the year. There can be several contributing factors, heat, rain, letting chemicals get out of balance, and even transfer form one pool to another. Recurring algae is usually Mustard Algae. It is a yellowish green color that usually starts growing on the pool walls and on the pool floor. It will then turn the pool water green. So how do you get rid of mustard Algae and keep it from coming back? First vacuum the pool on the waste setting. Mustard Algae is resistant to the normal chlorine levels so to get rid of Mustard Algae you can use a Yellow Out type product. To keep the Mustard Algae from returning to your pool you should use copper algaecide. Copper algaecide should be used as per the manufacturer instructions and should not be used during high levels of chlorine to prevent staining. Use clarifier to help filter out the algae and Metal Out or Demineralizer to prevent staining.