Cartridges & running costs

Identify the exact replacement family

Start with the cartridge compatibility directory if you do not know the family. Then use the relevant group below to check generation, fitting and replacement limits. Buying several refills at once only makes sense after those details agree.

Keep the model name of the jug or system alongside the cartridge name. Check the cartridge packaging, the system label and the current manufacturer instructions. A retailer listing can contain several packs, colours or generations under one page, so confirm the selected option at checkout.

For the jugs in our buying guide, the two cartridge families are BRITA MAXTRA PRO and Aqua Optima Evolve+. That is the first distinction to record; a broad search for “water filters” is not enough to select a replacement.

Before changing brands, read genuine versus compatible cartridges: mechanical fit, filtration evidence and service limits are separate checks.

BRITA jug cartridge families

MAXTRA families and cartridge purpose

BRITA offers Pure Performance and Limescale Expert within MAXTRA PRO. The manufacturer FAQ positions the latter for hard to very hard water. Think about your priority before ordering: everyday taste and kettle-scale reduction are related, but they are not the same requirement.

Do not use “fits BRITA” as a complete description. Confirm the exact cartridge family in the instructions for the device you own, especially when switching from an older product or buying a compatible-brand cartridge.

For the same Marella jug with a scale priority, compare the Limescale Expert type. BRITA’s specification explains its intended use.

• Pure Performance versus Limescale Expert explains the choice within MAXTRA PRO.
• MAXTRA+ versus MAXTRA PRO covers the generation change.
• MicroDisc versus MAXTRA PRO separates disc systems from jug cartridges.
• BRITA Classic compatibility is the route for the older, differently shaped family.

Other jug filters and refillable systems

Aqua Optima Evolve+

Aqua Optima says Evolve+ requires its compatibility key in BRITA PerfectFit jugs. Its fit guidance says current packs include the key and that older packs without it do not fit the newer PerfectFit jugs described there. Check what is actually supplied with your pack. Do not alter the jug to force a cartridge into place.

Cross-brand fit also does not establish identical filtration performance. Compare the claim and service-life instructions for the cartridge you are considering, rather than borrowing those of the cartridge it replaces.

Aqua Optima specifies 30 days or 100 litres for Evolve+. Enter those limits when budgeting; six filters do not guarantee six months if the volume limit comes first.

Read the Evolve+ compatibility-key guide before using an alternative pack in a PerfectFit jug.

ZeroWater, BWT and Philips

Brand names alone do not establish a fit. ZeroWater has a particularly important legacy-versus-new-system distinction; BWT also separates sealed and refillable options.

• ZeroWater cartridge compatibility: legacy filters vs newer Culligan systems
• BWT jug cartridge compatibility: sealed cartridges, refillable cartridges and granules
• Philips jug cartridge compatibility: matching Micro X-Clean filters to your model

For paired Evolve+ replacements, see the Perfect Pour dispenser guide.

Refillable shells and granules

The Aarke Purifier guide explains measured granule bags in a steel filter. The PHOX V2 guide covers fresh media in a retained cartridge shell. Both still need regular replacement media and cleaning; retaining a shell does not make used media last indefinitely.

Tap and under-sink replacement filters

The ON TAP V-MF manufacturer page names the compatible system generations and gives a four-month or 600-litre limit. These cartridges are separate from MAXTRA PRO jug filters.

For a Doulton installation, identify each stage separately. Doulton’s Biotect Ultra guidance names the M12 fitting and recommends changing the ceramic element around six months. The HIP TRIO also has two pre-filters with their own schedules.

Use ON TAP cartridge generations for tap-mounted BRITA systems. Use the Doulton identification directory to distinguish housing, fitting and ceramic grade before ordering.

Filter taps and multi-stage RO

• GROHE Blue cartridge compatibility: S, M and L sizes and specialist filters
• BRITA P 1000 vs P 3000: compatibility, capacity and replacement clearance
• How to replace Waterdrop G3P600 filters: CF, CB and RO cartridges
• RO remineralisation cartridges: what they change, compatibility and replacement costs

Gravity candles and appliance refills

Ceramic gravity candles

Use the Doulton identification directory to match the housing and candle. Then compare Ultra Sterasyl and Ultra Fluoride and check cleaning and replacement limits. These grades must not be mixed in one system.

Countertop appliances

Cube uses MAXTRA PRO, while Aurora and Lumi use their specified Evolve+ cartridges. The countertop RO shortlist distinguishes C1RF, K19RFG and A2RF; these are not interchangeable by brand name.

Calculate annual cartridge costs

For MAXTRA PRO, BRITA gives a maximum of four weeks or 150 litres. Local hardness and usage can shorten that life. Four weeks is not a calendar month: a full year divided into four-week periods is roughly thirteen changes, before allowing for heavy use.

Write the next change date down when you fit the cartridge. A bigger jug holds more water, but does not automatically give its cartridge a longer life. Use the dedicated running-cost calculator and worked examples before choosing a multipack.

Compare the pack and the replacement rule

Divide the current pack price by the number of cartridges. Then compare the right packs for your model and the cartridge type you want. Account for delivery and any subscription terms. Keep sealed spare filters according to the manufacturer's storage instructions and avoid buying more than you can sensibly store and use.

The lowest cost per rated litre can be misleading if a time limit arrives before you have filtered that volume. Budget using your expected consumption and the replacement limit that applies first.

Fit, maintain and recycle the cartridge

Use the MAXTRA PRO setup guide or Evolve+ setup guide for the exact preparation sequence. Keep a separate replacement schedule and indicator record. When a cartridge is removed, check the current UK recycling routes for its family.

For tap-mounted replacements, use the ON TAP change guide. For a multi-stage installation, the HIP TRIO ownership guide separates the ceramic refill from its two prefilters.

Choose media for the task: read activated carbon versus ion exchange and taste versus scale. A TDS meter cannot certify a cartridge’s remaining performance.

Questions about replacement cartridges