Vertex FK-101 + RO Membrane Complete Annual Filter Kit

For PT-505 and PT-4.0/5 Reverse Osmosis Systems

5-Stage Replacement Filter & Membrane Kit

Vertex FK-101 + RO Membrane Complete Annual Filter Kit - Pure n Natural Systems
Vertex FK-101 + RO Membrane Complete Annual Filter Kit - Pure n Natural Systems

Vertex FK-101 + RO Membrane Complete Annual Filter Kit

For PT-505 and PT-4.0/5 Reverse Osmosis Systems

5-Stage Replacement Filter & Membrane Kit

$193.18 $170.00
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About this product

Keep your reverse osmosis system performing like new with the PT-505 / PT-4.0/5 Complete 5-Stage Replacement Filter & Membrane Kit. This complete maintenance package includes the FK-101 5-stage replacement filter kit plus your choice of a 36 GPD or 50 GPD RO membrane.

Designed for the PT-505 and PT-4.0/5 reverse osmosis systems, this kit helps maintain cleaner, fresher-tasting water while supporting reliable system performance and filtration efficiency.

Key Features

  • Complete 5-stage filter and membrane replacement kit
  • Available with 36 GPD or 50 GPD RO membrane
  • Helps restore optimal RO system performance
  • Reduces sediment, chlorine taste, and odor
  • Supports cleaner, fresher drinking water
  • Compatible with PT-505 and PT-4.0/5 systems
  • Convenient annual maintenance solution
  • Helps extend reverse osmosis system lifespan

Membrane Options

Option Included Membrane Production Capacity
36 GPD Kit MA-4202 RO Membrane 36 Gallons Per Day
50 GPD Kit MA-4203-PWC RO Membrane 50 Gallons Per Day

 

This kit is compatible with 

Best for
  • PT-505 reverse osmosis systems
  • PT-4.0/5 RO systems
  • Annual RO filter maintenance
  • Residential drinking water filtration
  • Improving water taste and clarity
  • Reducing chlorine taste and odor
  • Maintaining consistent purified water production

Specifications
Product Name

PT-505 / PT-4.0/5 Complete 5-Stage Replacement Filter & Membrane Kit
Included Filter Kit / Membrane Options

FK-101

36 GPD or 50 GPD
36 GPD Membrane Model / 50 GPD Membrane Model

MA-4202

MA-4203-PWC
Compatible Systems

PT-505, PT-4.0/5
Filtration Stages / Application

5-Stage Reverse Osmosis Filtration

Residential Drinking Water
Replacement Type / Installation Type

Complete Annual Filter & Membrane Kit

Under-Sink RO System Maintenance
Membrane Type

Reverse Osmosis
Membrane Replacement Interval / Filter Replacement Interval

Every 2–3 Years Recommended

Approximately Every 6–12 Months

What's in the box
  • FK-101 5-Stage Replacement Filter Kit
  • Choice of RO membrane: MA-4202 36 GPD Membrane or MA-4203-PWC 50 GPD Membrane
  • Sealed replacement filter cartridges
  • Replacement RO membrane
  • Basic installation instructions

Installation tips
  • Turn off the water supply before servicing the system
  • Replace filters in the correct stage order
  • Sanitize housings during maintenance
  • Flush the new membrane before drinking water use
  • Inspect O-rings and seals during installation
  • Check all connections for leaks after startup
  • Replace filters annually for best results
  • Replace the RO membrane based on water quality and usage

Frequently asked questions

What systems is this replacement kit compatible with?

 This kit is designed for the PT-505 and PT-4.0/5 reverse osmosis systems.

What is the difference between the 36 GPD and 50 GPD versions?

 The difference is the membrane production capacity. The 50 GPD membrane produces more purified water per day than the 36 GPD membrane.

Does this kit include all replacement filters?

 Yes. The kit includes the FK-101 5-stage replacement filter set plus your selected RO membrane.

How often should I replace the filters?

 Most users replace the filters every 6–12 months, depending on water quality and usage.

How often should the RO membrane be replaced?

 RO membranes are typically replaced every 2–3 years, depending on incoming water conditions and system usage.

Will replacing the filters improve water taste?

 Yes. Replacing worn filters and membranes helps restore cleaner, fresher-tasting drinking water.

Can I install this replacement kit myself?

 Most homeowners can complete the replacement process using basic tools and the system owner’s manual.
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