The complete 6-12 month cartridge set for the MAW-50 reverse osmosis system: sediment, Matrikx carbon block, and inline carbon. Membrane sold separately.
The complete 6-12 month cartridge set for the MAW-50 reverse osmosis system: sediment, Matrikx carbon block, and inline carbon. Membrane sold separately.
Not sure which pack fits your system, or whether the membrane is due too?Text Aidan a photo of your under-sink unit and he will tell you in a minute which pack you need, and whether your TDS reading says the membrane should be replaced at the same time. No guesswork, no ordering twice.
NP5 sediment cartridge (the one in the clear housing)
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1
Matrikx carbon block (32-250-125-975)
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2
Inline carbon post-filter (NINCF-10-QC)
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1
Which pack do I need? Match the pack to your system configuration: the 4-stage pack fits the MAW-50 4-stage (SKU NRO4-50), the 5-stage pack fits the MAW-50 5-stage (SKU NRO5-50). The only difference is the second Matrikx carbon block the 5-stage system uses.
Every 6-12 MonthsThis filter pack. Change at 6 months on chlorinated city water or sediment-heavy wells, 12 months on cleaner feeds. The clear sediment housing on the MAW-50 shows you when the pre-filter is loading up.
Every 2-3 YearsThe RO membrane (sold separately). The TFC-50 replacement membrane ($135) handles the dissolved-solids removal and lasts 2-3 years when the pre-filters are changed on schedule. Replace sooner on hard or high-TDS water.
Changing the Filters
Close the feed valve and tank valve, then open the RO faucet to relieve pressure
Spin each housing off with the filter wrench included with your MAW-50
Swap the cartridges, check the double o-rings are seated, and hand-tighten the housings
Swap the inline carbon post-filter at the push-connect fittings
Reopen the valves, check for leaks, and flush the first full tank before drinking
Why the schedule matters: the carbon blocks protect the membrane from chlorine. Stretching a $49 filter pack past its life is how a $135 membrane dies early.
The exact factory cartridge set for the MAW-50, in the right count for your configuration
This is the exact replacement cartridge set for the MAW-50 reverse osmosis system, in the right count for your configuration. The 4-stage pack ($49) carries one NP5 sediment cartridge, one Matrikx extruded carbon block (32-250-125-975), and one inline carbon post-filter (NINCF-10-QC). The 5-stage pack ($59) adds a second Matrikx carbon block, matching the twin carbon stages that system runs ahead of the membrane.
Change the pack every 6 to 12 months: 6 on heavily chlorinated city water or sediment-heavy wells, 12 on cleaner feeds. The MAW-50's clear sediment housing shows you the pre-filter loading up, so you change on evidence instead of guesswork. The swap takes about 15 minutes with the filter wrench included with the system.
The RO membrane is deliberately not in this pack: it changes every 2 to 3 years, not every year. When your TDS reading starts creeping up, the TFC-50 replacement membrane ($135) is the other half of MAW-50 maintenance.
✔Fits MAW-50 4-Stage & 5-Stage
✔Replace Every 6-12 Months
✔Sediment + Carbon Block + Inline Carbon
✔From $49 Per Year
✔Membrane Sold Separately
✔ Expert Filter Change Support
From identifying your configuration to walking you through a housing swap on the phone, Aidan provides hands-on support at every step. Real person, real expertise, 30+ years of water treatment experience. No bots, no scripts.
📞 Call Us800-460-5810
✉️ Email Supportsupport@midatlanticwater.net
🕒 Live Hours7 days a week
Frequently Asked Questions
Match it to your MAW-50 system. The 4-stage pack ($49) fits the 4-stage system (SKU NRO4-50) and includes one NP5 sediment cartridge, one Matrikx carbon block, and one inline carbon post-filter. The 5-stage pack ($59) fits the 5-stage system (SKU NRO5-50) and includes a second Matrikx carbon block, because that system runs two carbon blocks ahead of the membrane. If you are not sure which system you have, count the vertical housings under your sink: three housings is the 4-stage, four housings is the 5-stage. Or call or text us at 800-460-5810 and we will sort it out.
Every 6 to 12 months. Change at 6 months if you are on heavily chlorinated city water or a sediment-heavy well; 12 months is fine on cleaner feeds. The MAW-50's clear sediment housing takes the guesswork out: when the cartridge looks loaded with sediment, it is time. Staying on schedule is what protects the RO membrane, which is the expensive part of the system.
No, and that is on purpose. The membrane changes on a different schedule (every 2 to 3 years) than the filters (every 6 to 12 months), so bundling them would make you pay for a membrane you do not need yet most of the time. When the membrane is due, the TFC-50 replacement membrane is $135 and swaps in the same horizontal housing. A cheap TDS meter on the RO faucet tells you when the membrane is fading: when the reading creeps up, it is membrane time.
About 15 minutes with the filter wrench that came with your MAW-50. Close the feed valve and tank valve, open the RO faucet to relieve pressure, spin off each housing with the wrench, swap the cartridges, check the double o-rings are seated, and hand-tighten the housings back on. The inline carbon post-filter swaps at its push-connect fittings. Reopen the valves, check for leaks, and flush the first full tank before drinking. No plumber needed.
The system keeps running, but the membrane pays the price. The carbon blocks exist to strip chlorine before it reaches the thin-film composite membrane; once the carbon is exhausted, chlorine degrades the membrane and your $135 membrane dies years early. A loaded sediment filter also drops the feed pressure to the membrane, which slows production. A $49-$59 pack once a year is the cheapest insurance in water treatment.
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MAW-50 Replacement Fil...$49.00
The Right Cartridges vs the Cheap Ones
What a no-name filter set can cost your membrane
What You Get With Generic Filter Sets
Generic 'universal RO filter sets' sold online often mix cartridge grades, skip the inline carbon, or substitute loose granular carbon for a true extruded carbon block. The price looks similar until a poorly sealed off-brand cartridge bypasses water around the media, or weak carbon lets chlorine through to the membrane. The savings on a $40 no-name set can cost you a $135 membrane.
The Real Cost Comparison
No-Name Filter Set
$35-$45
❌Lifespan: Fails in 3-4 years
❌Result: Frequent repairs, poor water quality, leaks
Exact factory cartridge set, Matrikx carbon block, expert support
At $49-$59 once a year, the filter pack is the entire running cost of MAW-50 ownership outside the $135 membrane every 2-3 years. That is a fraction of what a pitcher-filter habit costs annually, for water a pitcher cannot make.
What You Get With This Pack
These packs are the exact cartridge set the MAW-50 ships with: NP5 sediment, Matrikx extruded carbon block (one of the most widely respected carbon block brands in water treatment), and the matching inline carbon post-filter. Right cartridges, right count for your configuration, one order a year, and 7-day support from people who know the system they fit.
Contact Us
800-460-5810
We're here to help.
30-Day Guarantee
Consumables should be the easiest purchase you make all year
If anything in your filter pack arrives damaged, does not fit your MAW-50, or does not perform the way it should within 30 days, contact us and we will replace it or refund you. No restocking fees. No shipping cartridges back at your expense. No runaround.
10,000+Systems Installed
455+Verified Reviews
30+Success Rate
Replacement filters should be the easiest purchase you make all year: order the right pack, swap the cartridges, done. We back these packs the same way we back our systems, with real people answering the phone 7 days a week and 30+ years of water treatment experience behind them.
The "Final Sale" Consumables Trap
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Plenty of online filter sellers treat consumables as final-sale items or bury replacements behind restocking fees. For a $49 product that should never be a gamble. If the pack is not right, we make it right.
How Our Guarantee Works
1
Something's Not Right
Damaged cartridge, wrong fit, or performance that doesn't match what we promised: tell us within 30 days.
2
You Call Us, We Fix It
Most fit questions resolve in one text message with a photo of your system. If a cartridge is genuinely wrong or damaged, we ship the correct one immediately.
Replacement or Full Refund
If we cannot resolve the issue, you get a full refund. We handle the logistics. That is the difference between a real guarantee and a return policy.
Filter changes are where RO systems live or die. The number one thing I see kill membranes early is exhausted carbon blocks left in too long. Order the pack once a year, set a reminder, and your MAW-50 will quietly make great water for a decade. If you are not sure which pack fits your system, text me a photo of the unit and I will tell you in a minute.
