The AQUA Logic Inline Duo is a compact two-stage water filter set with separate carbon and ultra elements. Perfect for those who need just a bit more capacity than the C-Ultra, but do not require a large mainline system. Suitable for use under the kitchen sink or in campers, caravans and boats.
The Inline Duo consists of two connected 10” filter housings (Gen2) containing a carbon filter and an ultrafiltration membrane. Since carbon and ultra are designed as separate elements, they can be replaced individually. The larger full-size ultra membrane also provides greater capacity and a longer service life.
Filter characteristics
The AQUA Logic Inline Duo is a water filter that can be mounted between the water pipes of an existing pressurized water system. The filter improves the taste and quality of drinking water and is ideal for use at home, in caravans, campers, or yachts.
The Inline Duo consists of two connected filter housings containing
separate filter elements:
1. Activated Carbon cylinder with a pore size of 1 micron
The activated carbon is made from 100% organic material (coconut shell) and has a very high adsorption capacity for odours, colour, taste, metals such as lead, as well as yeasts, chlorine, pharmaceutical residues, and other chemicals.
2. Ultrafiltration membranes with a pore size of 0.01–0.03 microns (full-size)
Ultrafiltration membrames providing effective filtration against:
- Pathogenic organisms: Bacterial reduction of >99.9999% (including Cholera, Shigella, Typhus, Klebsiella terrigena, Legionella, and E. coli)
- Cysts/Protozoa: (including Giardia and Cryptosporidium)
- Micro- and Nano-plastics: Removes particles as small as 0.03 microns (30 nanometers)
All parts are BPA-Free. The filter works without the addition of chemicals and is made up of maintenance-free and corrosion-free parts.
How to use
1. Connecting the filter
Screw the supplied 3/8 inch hose barbs or 3/8 inch nipples with the O-rings into the lids so that the filter set can be placed between the cold water supply line. Pay attention to the flow direction (IN/OUT).
Note: the 3/8 inch hose barbs are intended for use with flexible hoses (with a hose clamp if necessary), as commonly found in recreational vehicles. For connection to a fixed water line, the 3/8 inch nipples are used in combination with 3/8 inch flexible braided hoses.
2. Mounting the filter system
Mount the filter system using the supplied wall bracket. Allow approximately 10 cm of space below the system so that the bowls and filter elements can be easily removed.
3. Marking the date of first use
Write the date of first use on the supplied date sticker and place it visibly on the filter housing. The recommended service life is 1 year; the actual lifespan of the filter elements depends on the degree of contamination in the source water. As long as water flows through the filters, it is safe to drink – even when the flow rate decreases.
4. Venting the system
Before first use, the filter system must be vented. Press and hold the black vent buttons on top of the filter lids (while the system is pressurized and the tap is closed) until all air has escaped.
Tip: hold a cloth near the vent valves to catch any water that may be released.
5. First use
It is recommended not to use the first 5 liters of filtered water for consumption. After this, the filter system is ready to provide clean and safe drinking water.
Maintenance
Relieve water pressure
Shut off the water supply and open the tap to release pressure from the system.
Remove the filter elements
Place a bowl or towel under the filters. Unscrew the bowls counterclockwise. Pull the filter elements out of the housings with a twisting motion.
Cleaning the carbon filter element
- Use the integrated cleaning pad to firmly scrub the surface of the carbon filter element.
- Rinse the carbon surface and ensure that only clean water touches the water outlet. As a precaution, do not use the first liter of filtered water for consumption.
Ultrafiltration element
The ultrafiltration membrane cannot be cleaned and must be replaced annually or sooner if the flow rate decreases significantly.
Reinstalling the filter elements
Place the filter elements back into the lids with a twisting motion. Screw the bowls back on; do not overtighten – tight is tight. Check that the rubber sealing rings are clean and properly positioned.
Venting after maintenance

Press and hold the vent buttons (while the system is pressurized and the tap is closed) until all air has escaped.
Tip: hold a cloth near the vent valves to catch any water that may be released.
Storage and winterizing
Wet storage: store the filter elements in a sealed container or bag in the refrigerator.
Dry storage: allow the filter elements to dry completely and store them in a clean place. Drying in the sun or near a heat source is recommended, but avoid direct contact of heat with the plastic parts.
Note: Although the filter housings are frost-resistant, it is important to drain the system during winter storage to prevent freezing.
Shelf life and Life Span
Unused, the filter has an almost unlimited shelf life (store in a cool, dry and dark place). The adviced service life is 1 year; the actual lifespan of the filter element may vary depending on the degree of contamination in the source water. As long as water continues to flow through the filter, it is safe to drink, even if the flow rate decreases.
Dimensions
(Click on the image below for a larger version)
Disclaimer
This water filter is designed to reduce a wide range of contaminants to levels generally considered safe for daily use. However, it may not be effective against water heavily contaminated with industrial chemicals or hazardous substances. Although water quality is significantly improved, the filter is not intended for specialized or medical use. Individuals with weakened immune systems or specific health concerns are advised to take extra precautions and consult a professional if necessary.