10" x 2.5" Carbon Block CTO Filter for RO Systems

10" x 2.5" Carbon Block CTO Filter for RO Systems

This 10" x 2.5" carbon block (CTO) filter is a standard pre-filter stage in most under-sink reverse osmosis systems. Carbon block filters are commonly used to help reduce chlorine taste and odor before water reaches the RO membrane.

Best for:

• Existing RO system owners replacing Stage 2 or Stage 3 carbon filters
• Anyone on a 6-month filter maintenance schedule
• Homeowners who notice chlorine taste or odor in their tap water

Key benefits:

• Carbon block construction provides consistent contact time with water
• Commonly used to help reduce chlorine taste and odor in drinking water
• Helps protect the RO membrane from chlorine-related degradation over time
• Standard 10" x 2.5" size fits most major RO filter housings

Compatibility:

Fits standard 10" x 2.5" filter housings used in most 5-stage under-sink RO systems. Compatible brands typically include APEC, iSpring, Express Water, Home Master, and Watts. Always verify your housing size before ordering.

What’s included:

1 x 10" x 2.5" carbon block CTO filter cartridge

Replacement schedule:

General guidance — every 6 months, or as recommended by your system manufacturer.

Installation notes:

DIY-friendly. Turn off the water supply and depressurize the system before replacing.

If you are responding to a local utility notice or boil-water advisory, follow your local utility or health department’s official instructions first.

Certification and contaminant reduction claims depend on manufacturer documentation for the specific product. Chloramine reduction claims require specific manufacturer test data — verify before purchase.

Frequently Asked Questions:

Does this filter reduce chloramines?
Carbon block filters are commonly used for chlorine reduction. Chloramine reduction depends on the specific product — verify with manufacturer documentation before purchase.

What does CTO stand for?
Chlorine, Taste, and Odor — the primary purpose of this filter stage.

How is carbon block different from granular carbon?
Carbon block filters have a denser structure that provides more contact time with water. Performance varies by product and application.

How often should I replace this filter?
Every 6 months is general guidance. Replace sooner if you notice taste or odor changes.

Does this have NSF certification?
Certification depends on the specific manufacturer documentation. Verify before purchase.

What if I received a water notice?
Follow your utility or health department’s official instructions first.