The Crystal Quest Nitrate Under Sink Water Filter System is a point-of-use drinking water filter designed to install beneath a sink and connect to the included faucet and installation hardware. It is available in single, double, and triple configurations, with the installation valve selected based on the home’s under-sink plumbing. The system uses a nitrate-selective cartridge designed to reduce nitrates from drinking water, with SMART and carbon block filtration stages included depending on the selected configuration. The nitrate cartridge is listed for 90% to 95% nitrate reduction, with performance depending on influent water conditions, water usage, and regeneration. With a 1/4" connection size, this under-sink nitrate water filter is intended for point-of-use drinking water applications in homes, apartments, offices, and similar settings where nitrate reduction is a treatment goal.
This Crystal Quest system installs beneath the sink to keep the filter housing off the countertop. It is designed for point-of-use drinking water applications where water testing has identified nitrate as a treatment concern and the included faucet setup is preferred.
The nitrate removal cartridge uses nitrate-selective media and is listed for 90% to 95% nitrate reduction, with performance dependent on influent water conditions. The cartridge requires manual salinity regeneration using sodium chloride brine, with regeneration timing based on influent nitrate level, water usage, and cartridge performance.
The nitrate cartridge is the core filtration stage. The single configuration includes the nitrate cartridge, the double configuration adds the SMART cartridge, and the triple configuration adds both SMART and carbon block filtration.
Select the installation valve based on the home’s under-sink plumbing and the installation manual. Crystal Quest states that a saddle valve is used for hard copper tubing, while a T-valve is required for flex tubing. A leak detector or flood-prevention valve may be considered as a recommended add-on for added installation protection where appropriate.
This under-sink nitrate water filter is designed for kitchens and point-of-use drinking water setups where under-sink placement is preferred. It connects below the sink and supplies filtered water through the included faucet setup.
Choose the configuration and valve option that match your available installation space, plumbing, and water test results. Single, double, and triple layouts support different cartridge combinations, while saddle-valve and T-valve selections support different under-sink plumbing setups.
Need help choosing the right nitrate under-sink filter?
TrueStead Supply can help you compare configuration size, connection type, and nitrate filtration needs.
✓ Nitrate-selective cartridge
✓ Manual sodium chloride brine regeneration
✓ Plumbing-based installation valve selection
| Brand | Crystal Quest |
| Product Type | Nitrate under sink water filtration system |
| Installation Type | Under sink, included faucet setup |
| Configuration Options | Single, double, or triple |
| Cartridge Mapping | Single: nitrate cartridge; Double: nitrate + SMART; Triple: nitrate + SMART + carbon block |
| Installation Valve Guidance | Saddle valve for hard copper tubing; T-valve for flex tubing, per Crystal Quest guidance |
| Connection Size | 1/4" |
| Primary Cartridge Type | Nitrate-selective media cartridge |
| Nitrate Reduction | 90% to 95%, based on listed source conditions |
| Nitrate Cartridge Capacity | Capacity varies by influent nitrate level and source-water conditions; system-specific source material lists 3,000 ppm of nitrates as CaCO3, while cartridge-only source material lists 5,500 ppm. |
| Replacement Cartridge SKU | CQE-RC-04007 |
| Replacement Cartridge Size | 2-7/8" × 9-3/4" |
| Regeneration Requirement | Manual salinity regeneration using sodium chloride brine |
| Water Testing Note | Nitrate reduction performance, regeneration timing, and cartridge service life depend on influent nitrate level, water usage, and source-water conditions; water testing is recommended before sizing or replacement planning. |
| Regeneration Timing | Varies based on influent nitrate level, water usage, and cartridge performance |
| Additional Cartridge Stages | Double configurations add SMART filtration; triple configurations add SMART and carbon block filtration |
| Max Flow Rate | 0.5 GPM |
| Operating Pressure | 20-60 psi |
| Operating Temperature | 40°F-90°F |
| Single Dimensions | 5" L × 14" H × 5" W |
| Double Dimensions | 10" L × 14" H × 5" W |
| Triple Dimensions | 15" L × 14" H × 5" W |
| Recommended Add-On | Leak detector / flood-prevention valve may be considered where appropriate |
| Installation Note | Follow the installation manual for faucet, valve, connection, and pressure-related setup requirements |
