Stainless Steel Undersink Replacement Filter Pack (4-stage)

• Complete Two-Filter Replacement Pack:
  Includes the filtration cartridges needed
  for compatible earlier four-stage
  undersink systems.
• Advanced Carbon Block Filtration:
  Features premium American-made filtration
  using 100% coconut shell activated carbon
  with a 0.5-micron nominal rating.
• Broad Contaminant Reduction:
  Designed to address chlorine, chloramine,
  lead, mercury, PFOA/PFOS, VOCs,
  and certain emerging contaminants.
• Optional Fluoride Reduction:
  Choose specialized filtration media
  designed to reduce fluoride alongside
  additional unwanted substances.
• Fine Particulate Filtration:
  Advanced carbon block technology
  provides mechanical reduction of
  fine particles, microplastics,
  and certain cysts.
• Improved Taste and Odor:
  Activated carbon filtration helps
  reduce chlorine and other substances
  that affect drinking water quality.
• Mineral Preservation:
  Designed to retain naturally occurring
  dissolved minerals, including calcium
  and magnesium.
• City and Well Water Applications:
  Suitable for compatible systems using
  municipal or well water, with
  performance dependent on incoming
  water conditions.
• Convenient Maintenance:
  Recommended replacement approximately
  every 6–12 months, depending on
  water quality and household usage.

Both replacement configurations provide
advanced drinking water filtration
designed for broad contaminant reduction.

The difference is the filtration
technology used in the second cartridge.

Standard Filtration

Our standard configuration combines
Advanced Carbon Block Filtration with
a complementary CTO carbon polishing
filter.

This combination is designed to address
chlorine, chloramine, certain heavy
metals, PFAS, VOCs, and other
unwanted substances.

The CTO polishing stage provides
additional chlorine reduction,
chemical adsorption, and improved
taste and odor.

With Fluoride Reduction

For households seeking fluoride
reduction, the standard CTO polishing
filter is replaced with specialized
filtration media designed to reduce
fluoride alongside other unwanted
contaminants.

This advanced media combines
complementary adsorptive and catalytic
filtration mechanisms to provide
an additional dimension of
contaminant reduction.

In addition to its intended fluoride
reduction function, the specialized
media is designed to address select
dissolved contaminants and support
reduction of certain chemical
substances, including chlorine,
chloramine, and organic compounds.

Fluoride may be present in municipal
water supplies or occur naturally
in groundwater.

If you’re unsure which configuration
best suits your water quality concerns,
our team is happy to help.

This replacement pack contains two
filtration cartridges for your existing
Greenfield undersink system.

Stage 1 — Advanced Carbon Block Filtration

A premium American-made carbon block
manufactured with 100% coconut shell
activated carbon.

Its 0.5-micron nominal filtration rating
provides fine particulate filtration
alongside broad chemical contaminant
reduction.

Designed to reduce chlorine, chloramine,
lead, mercury, volatile organic compounds
(VOCs), PFOA/PFOS, and certain emerging
contaminants, including pharmaceuticals.

This stage also provides mechanical
reduction of microplastics and certain
cysts, including Cryptosporidium
and Giardia.

Stage 2 — Your Choice of Filtration Media

Standard: CTO Carbon Polishing

A high-quality activated carbon block
provides additional chlorine reduction,
chemical adsorption, and final polishing
for improved drinking water taste
and odor.

This complementary carbon stage
provides additional filtration
for substances that can affect
water quality.

With Fluoride Reduction: Specialized Contaminant Reduction Media

For households seeking fluoride
reduction, the standard CTO
cartridge is replaced with
specialized filtration media
designed to address fluoride
alongside other unwanted contaminants.

This advanced media combines
complementary adsorptive and catalytic
filtration technologies to expand
the range of contaminants addressed
by the system.

Its filtration mechanisms are designed
to target select dissolved substances
while supporting additional reduction
of chlorine, chloramine, and certain
organic compounds.

Both configurations work alongside
our Advanced Carbon Block Filter
to provide broad contaminant reduction
while preserving naturally occurring
dissolved minerals.

Please Note:
The structuring and energizing device
is a permanent component of the
original system and does not require
routine replacement.

The filtration technologies used in
this replacement pack are selected
for their complementary approaches
to contaminant reduction and
drinking water quality.

Advanced Carbon Block Filtration

Our premium American-made carbon block
uses 100% coconut shell activated carbon
and features a 0.5-micron nominal
filtration rating.

This advanced filtration technology
is designed to reduce chlorine,
chloramine, lead, mercury, PFOA/PFOS,
VOCs, certain pharmaceuticals,
microplastics, and other emerging
contaminants.

The advanced carbon block has
performance data validated through
internal testing and independent
third-party laboratories.

Its materials are certified by
NSF International to NSF/ANSI
Standard 42 material requirements.
Contaminant reduction performance
is documented separately from
this certification.

Standard CTO Carbon Polishing

The standard second-stage carbon
block provides additional adsorption
of chlorine and certain organic
compounds, along with final
taste and odor polishing.

Specialized Fluoride Reduction Media

The optional fluoride reduction
configuration incorporates specialized
adsorptive and catalytic filtration
media designed to address fluoride
and additional unwanted contaminants.

These complementary filtration
mechanisms can provide additional
reduction of select dissolved
substances and certain chemical
contaminants.

Specific contaminant reduction
performance depends on the media
formulation and operating conditions.

Manufacturer testing provides
information about filtration
capabilities under defined conditions.

Actual performance can vary
depending on incoming water quality,
contaminant concentrations, flow rate,
household usage, and other
operating conditions.

Explore the available technical
documentation below.

Advanced Carbon Block Performance Data (PDF)

Standard CTO Carbon Block Performance Data (PDF)

An optional inline mineralizer
is available for customers who
prefer additional mineral enrichment
or a different drinking water
taste profile.

Greenfield filtration systems are
designed to preserve naturally
occurring dissolved minerals,
including calcium and magnesium.

The mineralizer is therefore
an optional addition rather than
a required component.

If your system includes an inline
mineralizer, please refer to the
installation instructions below.

Inline Mineralizer Manual (PDF)

For optimal performance, we generally
recommend replacing your undersink
filtration cartridges approximately
every 6–12 months,
depending on water quality and usage.

Larger households or homes with
higher water consumption will often
benefit from replacement closer to
every 6–8 months,
while smaller households with
lighter usage may be able to
go longer.

Incoming water quality, sediment
levels, contaminant concentrations,
and overall system usage can all
influence replacement frequency.

The service life of specialized
fluoride reduction media may also
vary depending on incoming fluoride
concentrations and overall water chemistry.

These recommendations reflect
our experience supporting Greenfield
filtration systems in real-world
household conditions.

Use the following resources for
filter replacement, installation,
and system sanitization.

Filter Replacement Manual (PDF)

Filter Replacement Video Guide

System Sanitizing Guide (PDF)

Questions about filter replacement,
filtration options, system compatibility,
or maintenance? Our team is happy
to help.