How to Treat & Prevent Algae

Algae is a major concern for any pool owner, but it is also easily preventable with the Sustain 3-Part System. Sustain is a high-quality product line that’s been proven effective at producing clean, sparkling, algae-free water for more than 25 years. In fact, it is so effective that the Sustain 3-part System comes with an Algae-Free Limited Warranty.

There are four general classes or types of algae found in swimming pools. The chart and information below will help you to identify and eliminate each:

Type Immediate Corrective Action Preventive Follow-up
Green or Black Algae, or Pink Bacteria


Check filter for proper operation and clean if dirty.

Use Sustain Shock Treatment according to label directions.

Maintain 1-3 ppm Free Available Chlorine (FAC). Re-dose Shield if <1.5 ppm. Adjust water return lines to improve circulation if needed.

Yellow (Mustard) Algae

Use an ammonium-based mustard algaecide with Sustain Shock Treatment according to label directions.

 

Green Algae

Green algae is free-floating and turns the water cloudy and green. This type is the most common and easiest to clear up. Use Sustain Shield Energizer Tablets or Sustain Shock Treatment according to label instructions. Circulate continuously for 24 hours, then retest the water for pH and FAC. Adjust pH to 7.2 - 7.4 and repeat application of Shock if algae color is not gone. Cloudiness may require another 24 - 72 hours of continuous circulation. (Tip: Watch the filter back-pressure and backwash/clean the elements as needed to maintain good circulation and to physically remove as much dead algae and debris as possible. Green algae exerts a tremendous chlorine demand, so the more that can be removed through filtration, the faster the chlorine will overcome the algae and the faster you'll clear up the problem.) If the pool water color doesn't improve after two applications, take a sample of your pool water to your Authorized Sustain Dealer.


Yellow (Mustard) Algae

Yellow algae is sometimes called mustard algae and appears on the pool surfaces as a fine dust. Typically, it is seen first on surfaces that don't receive direct sunlight. This algae is easy to brush off, but it frequently returns. Most pool experts agree that this type is the most difficult algae to control. Use Sustain Shock Treatment according to label directions and thoroughly brush the pool surfaces. Cleaning the filter and other equipment is especially important in controlling Yellow Algae. Circulate continuously and backwash the filter, cleaning the element as needed to maintain good circulation. When the problem is under control, backwash the filter and clean the element regardless of the back-pressure/flow rate. This will rid the pool and equipment of any algae that may remain trapped in the filter.


Black Algae

Black algae grows on the pool surfaces as dark spots. These colonies of algae will usually form in areas with less circulation. Black algae will feel slimy and will brush off with some effort. The algae grows into the pool surface and will be difficult to completely remove. Use Sustain Shock Treatment according to label directions and brush the affected areas frequently. Circulate continuously and back-wash the filter, cleaning the element as needed to maintain good circulation. When the problem is under control, backwash the filter and clean the element regardless of the back-pressure/flow rate. This will rid the pool and equipment of any algae that may remain trapped in the filter.


Pink Algae

Pink algae is actually bacteria. It forms colonies that have a slime layer. Pink algae is common in pools located near the oceans and Gulf waters, but can also show up inland, especially when swimmers have recently returned from vacationing on the coast. Use Sustain Shock Treatment according to label directions and brush all affected areas thoroughly and frequently. Wash all swimsuits and toys with dilute bleach. Circulate continuously and back-wash the filter, cleaning the element as needed to maintain good circulation. When the problem is under control, back-wash the filter and clean the element regardless of the back-pressure/flow rate. This will rid the pool and equipment of any colonies that may remain trapped in the filter.

Preventative Follow-up

 
After any occurrence of algae, have your pool water tested for the amount of Sustain Summer Shield Chlorine Extender. Re-dose if the level is less than 1.5 ppm. Maintain Free Available Chlorine (FAC) at 1 - 3 ppm and pH in the 7.2 - 7.4 range. Take a close look at the water circulation pattern to see if adjusting the return jet(s) will minimize dead spots. To maximize circulation, angle the return nozzles downward at a 45° angle and away from the skimmer. If you have more than one return, direct them all the same way so they work together.