1. Introduction
Welcome to the Max Water 20-inch Slim Blue Whole House Water Filter Set. This manual provides essential information for the proper installation, operation, and maintenance of your new water filtration system. Please read these instructions carefully before use to ensure optimal performance and longevity of the filters.
2. Product Overview and Components
This filter set includes three distinct 20" x 2.5" cartridges designed for comprehensive whole-house water filtration.
- Sediment Filter (SED): Made of polypropylene, this filter removes sand, dirt, rust, silt, and other particulate matter.
- Phosphate Anti-Scale Filter (PHO): Contains Siliphos balls to mitigate scale formation and corrosion, protecting plumbing and appliances.
- CTO Carbon Block Filter: Made from coconut shell carbon, this filter reduces chlorine, bad tastes, odors, THMs, and other organic compounds.

3. Specifications
| Feature | Value |
|---|---|
| Material | Carbon, Polypropylene |
| Product Dimensions | 2.5"D x 2.5"W x 20"H |
| External Testing Certification | NSF |
| Product Benefits | Removes sediment and impurities, mitigates scale and corrosion, and offers easy installation and compatibility. |
| Brand | Max Water |
| Unit Count | 1 Count |
| Number of Items | 3 |
| Item Weight | 6 pounds |
| Item Model Number | 20 x 2.5 Replacement Filter Set |
| Date First Available | May 21, 2019 |

4. Installation Guide
Before Installation
- Ensure the main water supply is turned off.
- Relieve pressure from the existing system, if applicable.
- Gather necessary tools (housing wrench, bucket, towels).
Filter Placement Order
For optimal performance, install the filters in the following sequence within your whole house filter housing:
- Stage 1: Sediment Filter (SED) - First stage for removing larger particles.
- Stage 2: Phosphate Anti-Scale Filter (PHO) - Second stage for scale and corrosion mitigation.
- Stage 3: CTO Carbon Block Filter - Final stage for taste, odor, and chemical reduction.

Installation Steps
- Unscrew the filter housings using a wrench.
- Remove old filters and dispose of them properly.
- Clean the inside of the filter housings.
- Insert new filters into their respective housings, ensuring they are centered.
- Hand-tighten the housings, then use the wrench for a quarter turn to ensure a snug fit. Do not overtighten.
- Slowly turn on the main water supply, checking for leaks.
- Flush the system for several minutes to remove any carbon fines or air.
5. Operating Instructions
Once installed, your Max Water filter set operates continuously to provide filtered water throughout your home.
Water Flow
Water enters the system, passes through the Sediment, then Anti-Scale, and finally the CTO Carbon Block filter before exiting as filtered water for your entire house.

Initial Flush
After installation, allow water to run through the system for at least 10-15 minutes to flush out any carbon dust from the CTO filter and air from the lines. This is normal and ensures optimal performance.
6. Maintenance and Filter Replacement
Filter Life Expectancy
- Sediment Filter (SED): 6-12 months
- Phosphate Anti-Scale Filter (PHO): 2-12 months (Note: This filter cannot work as a primary filter and must be removed after the sediment filter to prolong filter life.)
- CTO Carbon Block Filter: 6-12 months
Filter life can vary based on water quality and usage. Regular inspection is recommended.
Replacement Procedure
- Turn off the main water supply.
- Relieve pressure from the system.
- Unscrew filter housings and remove old filters.
- Clean housings and replace O-rings if necessary.
- Insert new filters, ensuring correct order.
- Hand-tighten housings, then use a wrench for a final snug fit.
- Slowly turn on water supply and check for leaks.
- Flush the system for 10-15 minutes.
7. Troubleshooting
- Low Water Pressure
- This may indicate clogged filters. Check filter life expectancy and replace if due. Ensure proper installation and no airlocks.
- Water Leaks from Housing
- Ensure housings are tightened correctly. Check O-rings for proper seating, damage, or dryness. Apply food-grade silicone grease to O-rings if needed.
- Cloudy Water After Filter Change
- This is typically carbon fines from the new CTO filter. Flush the system for a longer period (15-20 minutes) until water runs clear.
- Unpleasant Taste or Odor Returns
- The CTO carbon filter may be exhausted. Replace the CTO filter.
8. Safety Information
- Do not use with water that is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system.
- This filter set is designed for cold water applications only. Do not exceed the maximum operating temperature.
- Ensure all connections are secure to prevent leaks.
- Keep out of reach of children.
- Dispose of used filters according to local regulations.
Important Note: This cartridge WILL NOT remove chemicals or disinfect water. Its primary purpose lies in serving as a comprehensive whole-house water filter, effectively managing iron and calcium levels in the water.

9. Warranty and Support
For warranty information or technical support, please contact Max Water customer service. Refer to your purchase documentation for specific warranty terms.
You can visit the Max Water Store for more products and support: Max Water Store