Carbon Block CTO Cartridge – 10 Inch Slim | UV Water Systems Oman

The carbon block CTO (Chlorine, Taste, Odour) cartridge is the second stage in a standard residential RO system — positioned after the sediment pre-filter and before the RO membrane. Its primary and most critical function is dechlorination: removing residual free chlorine from PAEW’s chlorinated municipal water supply before that water contacts the RO membrane. Thin-film composite (TFC) RO membranes — the standard in all quality residential and commercial RO systems — are highly sensitive to chlorine oxidation. Free chlorine at typical Oman municipal concentrations (0.2–0.5 mg/L) progressively degrades TFC membrane polymer, creating micro-holes that allow dissolved solids to bypass the rejection layer — reducing membrane rejection from the designed 96–98% down to 70–80%, at which point the treated water quality is no longer acceptable. Carbon block filtration before the membrane eliminates free chlorine completely, protecting the membrane and extending its service life from 1–2 years (unprotected) to 3–5 years (protected). UV Water Systems in Muscat supplies carbon block CTO cartridges for all residential and commercial RO pre-treatment applications across Oman.

Carbon Block vs. Granular Activated Carbon for RO Pre-Treatment

Both carbon block and granular activated carbon (GAC) cartridges remove chlorine — but carbon block does it more reliably. In a GAC cartridge, water can channel through the loosely packed granules and bypass some of the carbon, receiving incomplete dechlorination. Carbon block cartridges are manufactured by sintering activated carbon particles into a solid matrix — water cannot channel through the block and must pass through the full carbon mass, achieving complete and reliable dechlorination even at rated maximum flow rates. For RO membrane protection, where chlorine breakthrough — even brief — can cause irreversible membrane damage, carbon block is the correct pre-treatment choice.

Key Features and Benefits

Complete dechlorination at rated flow: Sintered carbon block construction eliminates channelling — water contacts the full carbon mass at all flow rates, achieving complete free chlorine removal to below 0.1 mg/L before the RO membrane at rated 10-inch slim flow rates.
Removes THMs and VOCs: Beyond chlorine removal, activated carbon adsorbs trihalomethanes (THMs) and volatile organic compounds (VOCs) present in chlorinated municipal water — reducing these disinfection by-products in the RO pre-treatment feed.
Taste and odour improvement: Carbon adsorption removes the chlorine taste and odour that makes Oman municipal water unpleasant to drink unfiltered — even before the RO stage provides full mineral reduction, the CTO stage significantly improves the taste of filtered water.
Standard 10-inch slim dimensions: Compatible with all standard under-sink RO system second-stage housings — no adapters required for installation in UV Water Systems RO systems or third-party systems using 10-inch slim second-stage carbon filters.
6-month replacement interval in Oman conditions: Oman’s chlorinated municipal supply exhausts carbon adsorption capacity within 6 months at typical residential water consumption — replacing on schedule maintains full dechlorination protection for the RO membrane and avoids costly early membrane replacement.

Technical Specifications

Length: 10 inches (254 mm) nominal
OD: 2.5 inches (64 mm)
Filter type: Carbon block (sintered)
Removal targets: Chlorine, THMs, VOCs, taste, odour
Max operating temp: 52°C
Recommended replacement: Every 6 months

Applications Across Oman

The 10-inch slim carbon block CTO cartridge is the standard second-stage pre-filter in under-sink RO systems installed across Muscat. UV Water Systems includes carbon block cartridge replacement in all residential RO maintenance contracts — call +968 9763 7786 to schedule a maintenance visit or to order replacement cartridges for self-installation.

Frequently Asked Questions

Can I use a GAC cartridge instead of a carbon block for RO pre-treatment? A GAC cartridge is not recommended as the sole dechlorination stage before an RO membrane. Channelling through loose granules can allow chlorine breakthrough — UV Water Systems always uses carbon block cartridges in the dechlorination stage of RO pre-treatment systems to ensure complete and reliable membrane protection.

What happens if I don’t replace the CTO cartridge on time? An exhausted carbon block loses its chlorine adsorption capacity — free chlorine passes through to the RO membrane. Initial damage is invisible but progressive — the membrane’s TFC layer oxidises and develops micro-defects that increase TDS passage. By the time performance decline is noticeable, significant membrane damage has already occurred. Prevention through timely cartridge replacement is dramatically cheaper than membrane replacement.

UV Water Systems is an ISO 9001:2015 certified water treatment company based in Muscat, Sultanate of Oman, with 14+ years of experience. We supply, install, and service water treatment solutions for residential, commercial, and industrial clients across Oman. Call +968 9763 7786 or visit www.uvwater.biz.

Carbon Block Cartridge Oman

Carbon Block CTO Cartridge 10 Inch Slim – UV Water Systems Oman