Step 1 of the Sustain 3-Step Pool Care System.

The quart size of Sustain Summer Shield Chlorine Extender — same formula as the half-gallon, sized for smaller pools or for topping up mid-season. Summer Shield works by creating a reserve bank of chlorine in your pool water that releases on demand whenever routine sanitizer levels drop below 1 ppm. After a heavy rain, a busy weekend, or a pool party, your pool already has the chlorine reinforcement it needs — automatically.

Summer Shield also includes a built-in clarifier to help your filter pull suspended particles out of the water for brighter, more brilliant results.

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

Pack size: 1 quart (32 fl oz)
Application: Once a summer (for chlorinated pools only)
Use with: Sustain 3" Chlorinating Tablets (Step 2) and Sustain Shield Energizer Tablets (Step 3)

Note: For proper performance, Summer Shield should measure 1.5–5 ppm. Have us test your Shield level every six weeks.

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