Step 1 of the Sustain 3-Step Pool Care System — the foundation of season-long algae protection.

Sustain Summer Shield Chlorine Extender adds an extra layer of protection to your pool by creating a reserve bank of chlorine fighting power that releases on demand — automatically — whenever routine sanitizing levels drop below 1 ppm. That means after a rainstorm, a pool party, or a heavy bather load, your pool already has backup chlorine waiting to step in. No emergency shocking, no green-water surprises.

Summer Shield also contains a built-in clarifier that gathers suspended particles, making them easier for your filter to remove — for noticeably brighter, sparkling water.

Used according to label directions, one application lasts all summer (up to 150 days).

Pack size: ½ gallon (64 fl oz)
Treats: up to 20,000 gallons
Application: Once a summer (for chlorinated pools only)
Use with: Sustain 3" Chlorinating Tablets (Step 2) and Sustain Shield Energizer Tablets (Step 3)

Note: Summer Shield levels can be affected by splash-out and water dilution. To ensure proper levels, have us test your Shield level every six weeks. For Summer Shield to be effective, it must measure 1.5 ppm to 5 ppm.

Sustain® and Summer Shield® are registered trademarks of Westlake Corporation.