Pool Maintenance Tip #4 – the last in our Pool Algae Series – Yellow/Mustard Algae Yellow or Mustard algae is very similar to green algae, but it is much slower growing and does not have the green pigment (chlorophyll) which accounts for its yellow color. Because Yellow algae is slow growing, it is very difficult to destroy. By the time you see it in your pool, it has probably been growing for several days or even weeks. Also, since it is low in chlorophyll which likes light, it can grow in dark areas of the pool – plumbing, pump pots, filters, etc. It is very important that you select the correct algaecide for Yellow algae. Copper-based algaecides work well and remember to follow the instructions on the label. Yellow algae can be tough so don’t be surprised if you need to treat it more than once. This points out the value of preventing algae growth to begin with. A weekly or monthly maintenance dosage of an algaecide and testing your pool water daily for sanitizer levels goes a long way towards prevention. For more pool maintenance tips from your Houston Pool Builder, check out our facebook page or contact our pool service department.