United Chemical Yellow Treat algaecide — 2 lb concentrated mustard & yellow algae killer for saltwater and chlorine pools

Yellow Treat is a concentrated algaecide formulated to eliminate mustard and yellow algae quickly in both saltwater and chlorine pools.

Introduced in 1981, United Chemical's Yellow Treat has earned a reputation for fast, reliable control of yellow and mustard algae without leaving stains or damaging pool surfaces. A small dose goes a long way—just 5 ounces treats 10,000 gallons—so you can tackle even persistent blooms with minimal shock treatment and less effort. The granular formula dissolves directly into pool water, works across pool systems and types, and is safe for above-ground and inground pools when used according to directions.

How fast will Yellow Treat clear yellow or mustard algae?

Yellow Treat acts quickly on the algae cells, often showing visible improvement within 24 hours and substantial clearing within a few days depending on severity. Results vary by water temperature, circulation and initial algae concentration, but the product is designed to accelerate recovery compared with standard algaecides.

• Visible change commonly within 24 hours for light to moderate blooms.
• Heavier infestations may require follow-up applications and brushing.
• Works faster when combined with proper filtration and a single shock treatment.

Can I use this in saltwater and chlorinated systems?

Yes — the formula is compatible with saltwater pools, traditional chlorine systems and freshwater pools, making it versatile for most backyard setups. It dissolves directly into pool water and integrates with existing sanitation routines without special equipment or complex preparation.

• Safe for both salt-chlorine and standard chlorine pools when dosed as directed.
• No extra additives required; simply pour, brush and allow circulation.
• Does not interfere with routine sanitizer levels when used properly.

Will Yellow Treat damage pool surfaces or cause staining?

Yellow Treat is formulated to be tough on algae but gentle on pool finishes and surrounding materials. The product contains no staining ingredients, so treated surfaces remain unchanged when you follow the label instructions for dosing and circulation.

• Safe for vinyl, plaster, fiberglass and painted surfaces.
• No staining ingredients included in the formula.
• Rinse or brush surfaces as directed for best results and appearance.

How do I use Yellow Treat for best results?

Dosage is straightforward: 5 ounces treats 10,000 gallons. For typical application, pour the measured amount into the pool at evenly distributed points, brush areas with visible algae to loosen growth, and run the filter continuously until water clears.

• Measure carefully: 5 ounces (one bag or capful) per 10,000 gallons.
• Pour granules into the deep end or along pool perimeter for even dispersion.
• Brush affected surfaces and keep filtration running until clarity returns.

Who this is for: United Chemical Yellow Treat is intended for homeowners, pool service technicians and commercial pool managers who need a dependable, concentrated solution for yellow and mustard algae. It’s ideal when you want a rapid, low-volume treatment that works across pool types—above-ground and inground, saltwater and chlorine—without staining surfaces or requiring complex handling. Use Yellow Treat when you want pro-level algae control with a minimal dose and straightforward application to restore clear, swimmable water fast.