How often should cartridges be replaced? Generally every 6 to 12 months, with the actual cycle depending on usage, incoming water and cartridge type:
- PP cotton and pre-activated carbon: generally every 6 months.
- Activated Carbon: generally every 12 months.
- UF membrane and RO membrane：壽命較長，視用水量及水質而定（RO 膜一般兩至三年）。
Shorten the cycle with heavy use or poorer water; regular replacement is the non-negotiable part of keeping water quality and equipment performance up.
In an age that prizes healthy drinking water, the filter cartridge is the core of water-quality management. From straining out sediment to reducing heavy metals, bacteria and odours, each cartridge technology has its own job and its own audience. Whether the cartridge is right directly shapes the water and the machine's lifespan — true of a home under-sink system, and truer still of high-volume commercial systems. This guide covers the eight cartridge technologies — PP cotton, activated carbon, UF membrane, reverse osmosis (RO) membrane, ceramic, ion exchange resin, ultraviolet (UV) disinfection and composite cartridges — introduces the surrounding topics, and links to in-depth articles on each, so your drinking water stays clean and safe.
Why does cartridge choice matter so much?
A filter is only as good as its cartridges, and different cartridges target different contaminants. Hard-water areas need softening; well-water users must prioritise bacteria. The wrong choice can mean poor water — or damaged equipment. Understanding each cartridge's function, life and place is the first step to filtration that works. Below is an overview of the eight technologies; follow the links to read each in depth.
The eight cartridge technologies at a glance
1. PP cotton: the solid first line of defence
The PP cotton (polypropylene) cartridge is the system's first line of defence, removing sediment, rust and larger suspended matter and keeping later cartridges clear. Economical, it fits every kind of equipment.
- Strengths: low cost, filters larger particles, extends the life of the stages behind it.
- Limits: no effect on chemicals or bacteria; needs frequent replacement.
- Where it fits: pre-filtration, home and commercial systems.
- Read more：Filter Cartridge Series (1): PP Sediment Filters, the First Line of Defence
2. Activated carbon: the adsorption specialist
Known for its adsorption capacity, activated carbon removes chlorine, organic compounds, odours and some chemicals, markedly improving taste. It serves in both pre- and post-filtration, protecting other cartridges while improving the water.
- Strengths: better taste, no chemical residue, works pre- and post-filtration.
- Limits: no effect on heavy metals or bacteria; needs regular replacement.
- Where it fits: mains supply, under-sink filters, commercial dispensers.
- Read more：Filter Cartridge Series (2): Why Activated Carbon Is Indispensable
3. The UF hollow-fibre membrane: precision filtration
With 0.01-micron pores, the UF (ultrafiltration) hollow-fibre membrane removes bacteria, viruses and fine particles with precision while keeping the water's beneficial minerals. Needing no power, it suits users after a natural water profile.
- Strengths: removes micro-organisms, keeps minerals, saves energy.
- Limits: no effect on heavy metals or dissolved solids; wants pre-filtration.
- Where it fits: central filtration, drinking water purification, outdoor filtration, commercial kitchens.
- Read more：Filter Cartridge Series (3): The UF Hollow-Fibre Membrane
4. The reverse osmosis (RO) membrane: high-precision filtration
The RO membrane is high-precision filtration, with pores around 0.0001 micron, helping reduce dissolved solids, some metal ions, salts and particulates. Actual results depend on the water, system design, installation and cartridge upkeep — so think of it as a high-precision option to configure where needed, not something to describe as guaranteeing removal of every contaminant, or as a health promise, or the only answer.
- Strengths: helps reduce a wide range of dissolved impurities, salts and some metal-related concerns — for settings with higher expectations of purity.
- Limits: can produce reject water, needs power or pressure, and needs cartridges and the membrane replaced on a usage-based schedule.
- Where it fits: home drinking water, F&B, offices, schools and venues with clear water-quality requirements.
- Read more：Filter Cartridge Series (4): The RO Membrane
5. Ceramic: the durable natural choice
The ceramic cartridge's micro-porous structure filters bacteria, particles and suspended matter, and it can be cleaned and reused. Made from natural material, it suits the environmentally minded.
- Strengths: cleanable and reusable, removes bacteria, long-lived.
- Limits: no effect on chemicals or heavy metals; slower flow.
- Where it fits: outdoor purification, hard-water areas, simple systems.
- Read more：Filter Cartridge Series (5): The Natural Filtration of Ceramic Cartridges
6. Ion exchange resin: hard water's nemesis
Ion exchange resin removes hardness ions — calcium and magnesium — by chemical exchange, preventing scale, protecting equipment and making water pleasanter to use. It serves hard-water areas and multi-stage systems as a supporting cartridge.
- Strengths: softens water, protects equipment, regenerable.
- Limits: no effect on organics or bacteria; needs regular regeneration or replacement.
- Where it fits: hard-water areas, water heater protection, industrial water.
- Read more：Filter Cartridge Series (6): Ion Exchange Resin and Water Softening
7. Ultraviolet (UV) disinfection: the microbial safeguard
UV systems use 254-nanometre UV-C light to inactivate bacteria, viruses and parasite cysts, with no chemicals added, helping keep water management steady. It runs standalone or as the final stage of a multi-stage system.
- Strengths: efficient disinfection, no chemical residue, simple to run.
- Limits: no effect on heavy metals or organics; needs power.
- Where it fits: well water purification, commercial drinking water, medical institutions.
- Read more：Filter Cartridge Series (7): UV Disinfection for Added Assurance
8. Composite cartridges: integration made convenient
A composite cartridge folds PP cotton, activated carbon, an RO or UF membrane into a single unit, purifying in stages while simplifying maintenance and saving space. It suits users after convenience and efficiency.
- Strengths: all-round purification, simpler maintenance, compact design.
- Limits: constrained by materials, varied lifespans, higher cost.
- Where it fits: under-sink filters, commercial systems, compact equipment.
- Read more Filter Cartridge Series (8): Composite Cartridges
Beyond the cartridges: more purification topics
Beyond the eight technologies, these articles broaden the picture and help you get more from your filter:
- Keeping cartridges effective: water testing and filter maintenance: learn how testing and regular maintenance keep cartridges performing over the long term.
- Choosing the right filtration system: home and commercial cartridge applications: explore how to choose a system for home or business, weighing cartridge technology alongside installation.
How to choose the right cartridge
Choose by water quality, purpose and budget. Some practical advice:
- Water-quality problems：
- Sediment and suspended matter: choose PP cotton as the primary filter.
- Chlorine and odours: activated carbon serves in both pre- and post-filtration.
- Metal-related concerns (such as lead and copper): if old pipework or the building's supply system raises metal-related worries, look at water test results first, then compare RO and other higher-precision point-of-use options as needed.
- Microbial concerns: cartridges differ in how they handle bacteria, viruses and particulates — judge by source, specification, certification information and upkeep, not by rule of thumb.
- Hard water and limescale: ion exchange resin softens effectively.
- Multiple contaminants: composite cartridges or multi-stage systems (such as RO plus activated carbon) purify across the board.
- Where it fits: home filters favour convenient composite cartridges or RO systems; commercial settings need high-flow UF.
- Maintenance cost: PP cotton, activated carbon and composite cartridges need frequent replacement; ceramic can be cleaned and reused; UF and RO membranes last longer, depending on the water.
- Budget: PP cotton and activated carbon cost less; an RO system asks more upfront but pays off over time.
The keys to cartridge maintenance
Whichever cartridge you choose, regular maintenance is what safeguards the water:
- Replacement cycle: replace cartridges as the guidance directs, adjusted for water quality and usage (generally 6 to 12 months).
- PP cotton and pre-activated carbon: generally every 6 months, to keep sediment, chlorine and odours in check.
- Post-activated carbon and the UF membrane: generally every 12 months, to hold taste and bacteria removal.
- RO membrane：一般兩至三年更換，確保全面（包括重金屬）的過濾效果。
- Watch the water: slower flow, duller taste or more scale can mean a clogged or spent cartridge — call in professional service.
- Cleaning and care: ceramic can be brushed regularly; RO systems need their reject water and TDS checked; UV lamps are replaced per guidance.
- Professional support: choose a dependable brand for cartridge quality and after-sales service — Bio-Link's maintenance plans provide full support (see the complete filter and dispenser maintenance guide).
Filtration precision summary table
| Filtration method | Filtration rating | Contaminants addressed |
|---|---|---|
| Reverse osmosis (RO) | 0.0001 micron | Bacteria, viruses, heavy metals, salts |
| Ultrafiltration (UF) | 0.01 – 0.1 micron | Bacteria, viruses, protozoa, colloids |
| Polypropylene (PP) | 0.1 – 50 microns | Sediment, rust, larger particles |
| Activated carbon cartridge | 1 – 10 microns | Odours, residual chlorine |
Conclusion
Filter cartridges are a vital part of drinking water management. From PP cotton's primary filtration to the composite cartridge's all-in-one integration, each technology has its place. Understand the eight cartridges' functions and limits, match them to your water, installation and maintenance, and you can choose a purification set-up with confidence. Where old pipes, sediment or metal-related concerns are involved, ground the decision in water-quality data and professional assessment before settling on RO, UF or a multi-stage configuration.
Choosing a home Water Purifier or RO water dispenser? Compare Bio-Link's current home solutions first, by installation space, usage and whether you need instant hot water:
- RO838: for households wanting an under-sink RO filter, using filtered water for daily cooking and drinking.
- DT400: suitable for homes that want a tabletop instant-hot water dispenser with filtration options chosen to suit on-site conditions.
Choosing the right Office Water Dispenser? Compare Bio-Link's current commercial solutions first, by headcount, pantry space, hot and cold water needs and maintenance arrangements:
- ST1523: suited to medium and large offices or busy shared pantries, with higher capacity and RO filtration.
- ST9102: suited to schools, educational institutions or shared venues that need durable design and fixed maintenance arrangements.
- STC15: suited to small offices, clinics or studios with limited space, supporting more compact commercial installations.
For offices, schools and commercial venues, the right dispenser and cartridge maintenance arrangement is more than equipment management — it cuts water deliveries, storage and bottled water handling, supporting operational reliability and plastic-reduction and ESG goals.
Why choose Bio-Link?
Bio-Link was established in Hong Kong in 1997, providing one-stop consultation, installation and maintenance for filtration systems and hot-and-cold water dispensers across Hong Kong and Macau. Bio-Link has long focused on water filters and drinking water equipment, helping homes, offices, F&B businesses, hotels, educational institutions, community centres, medical institutions, research laboratories and other venues choose the right drinking and filtration solutions for their actual needs. For users worried about old pipework, sediment or cartridge replacement, start by understanding the site's water and equipment, then pair the right filtration equipment with regular maintenance and cartridge replacement.
Bio-Link provides convenient professional on-site cartridge replacement to keep your filtration system at its best. Our technicians match cartridges precisely to your water needs and equipment model, then install and test them — no need to do it yourself, and the system lasts longer for it.
Further Reading:Everpure PBS-400 filter cartridge.
Frequently asked questions
What types of filter cartridge are there, and what does each do?
The common types: the PP cotton (melt-blown) cartridge, removing sediment, rust and larger particles; the activated carbon cartridge, adsorbing chlorine, odours and some organics. The UF hollow-fibre membrane removes bacteria and colloids while keeping the water's minerals; the RO membrane filters dissolved solids and some metal ions with high precision. The ceramic cartridge filters physically and can be washed and reused; ion exchange resin handles calcium and magnesium, softening the water. UV disinfection disrupts the DNA of bacteria and viruses. Most systems combine several cartridges to match their filtration goals. See PP sediment filter,Activated Carbon and the other articles in the series for the details.
How often should cartridges be replaced?
更換週期因濾芯類型、日常用水量及原水水質而有所不同。一般參考：前置濾芯一般每年更換（高用量場地會較密）；RO 膜一般兩至三年，實際週期以保養安排為準；UF 超濾膜視型號而定，部分可定期沖洗清潔後繼續使用。建議以廠商說明書為準，並根據實際用水量和水質情況作調整。不要單靠感覺判斷是否需要更換——超期使用的濾芯有機會令過濾效果下降，甚至成為細菌滋生的隱患。
How do I know my filter's cartridges need changing?
The common signs: flow noticeably slower or pressure down; a change in taste or smell; unusual colour or clarity; or the manufacturer's recommended period reached or passed. Some equipment has a replacement reminder; without one, track the cycle yourself and schedule changes. With a maintenance contract (such as Bio-Link's on-site service), technicians arrange replacement on schedule — nothing to track yourself.
What does a multi-stage system offer over a single cartridge?
A multi-stage system sets a dedicated cartridge against each type of impurity, each stage doing its own job, for a more complete result than any single cartridge. In a four-stage RO configuration, for instance, the PP cotton pre-filter takes the larger particles, activated carbon handles odours, and the RO membrane finishes with high-precision filtration — a clear division of labour. Configure by actual need: more stages is not automatically better; what matters is whether each stage matches the goal and the environment.
Related Further Reading
To see the cartridges Bio-Link can replace and the services available, go to Filter Cartridge page.
Cartridge replacement needs vary by setting. Schools, restaurants and hotels can see School Water Dispenser,Restaurant Water Filtration Systems and Hotel Water Filtration System.