Whole Home Water Filter Replacement Cartridge 4.5'x20' PHO Scale Inhibitor

Protect Your Pipes. Extend Your Appliances' Life.

The Ninety PHO Scale Inhibitor Replacement Cartridge is designed for whole-home water filter systems, effectively preventing limescale buildup in pipes, boilers, and heating equipment — keeping your home's water infrastructure running efficiently for longer.

Key Features

• Scale inhibition: Polyphosphate beads slowly release protective agents that bind with calcium and magnesium ions, preventing scale formation
• Water softening: Reduces water hardness, protecting appliances and plumbing from corrosion and mineral deposits
• Universal fit: Standard 4.5" × 20" size — compatible with most whole-home filter housings on the market
• Easy replacement: No modifications required, installs in minutes
• Long-lasting performance: Silica-phosphate bead fill for sustained, consistent protection

Technical Specifications

• Cartridge size: 4.5" × 20" (standard Big Blue format)
• Filter media: Polyphosphate (PHO) silica beads
• Function: Scale inhibition, water softening, corrosion protection
• Compatibility: Most standard whole-home filter housings

What's in the Box

• 1 × PHO Scale Inhibitor Replacement Cartridge (4.5" × 20")

When to Replace

Replace every 6–12 months depending on your local water hardness and household consumption. Regular replacement ensures optimal scale protection and water quality.

Ideal for homes with hard water, protecting boilers, washing machines, dishwashers, and all plumbing from costly limescale damage.