
Express Water RO5DX
Score: 88/100
Aquasana Direct Connect
Score: 88/100Rankings

The Express Water RO5DX is a certified 5-stage under-sink reverse osmosis system that produces 50 gallons of purified water daily. It features NSF/ANSI 58 certification and an alkaline remineralization stage for improved taste. It is best suited for households of 4+ people seeking reliable, certified water purification with a compact footprint.

The Aquasana Claryum 3-Stage Max Flow Under Sink Water Filter is a high-capacity filtration system that reduces up to 99.99% of 78 contaminants while retaining beneficial minerals like calcium and magnesium. It features a 44% faster flow rate of 0.72 gpm and an 800-gallon capacity, certified by WQA to NSF/ANSI Standards 42, 53, and 401. It is best for households seeking high-capacity under-sink filtration without reverse osmosis.
| Attribute | ![]() | ![]() |
|---|---|---|
— | 800 gallonsbest | |
0.8 gpmbest | 0.72 gpm | |
5best | 3 | |
1 yearsbest | 1 yearsbest | |
96 percentbest | 0 percent | |
— | 20 psibest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Safety & Compliance(1) | ||
Certifications | NSF/ANSI 58 | NSF/ANSI 42, 53, 401, WQA |
Installation & Compatibility(2) | ||
Installation Type | Under-sink | Under Sink |
Faucet Compatibility | Standard Kitchen Sinks | Standard Sink with Hole |
Filtration Performance(6) | ||
Filtration Technology | Reverse Osmosis | Claryum |
Flow Rate (gpm) | 0.8 gpm | 0.72 gpm |
Contaminants Removed | Lead, Chlorine, Fluoride, Arsenic, Nitrates, PFAS, Bacteria, Pharmaceuticals | Chlorine, Lead, PFAS, Microplastics, Cysts, VOCs, Asbestos |
Filtration Stages | 5 | 3 |
TDS Reduction (percent) | 96 percent | 0 percent |
Operating Pressure (psi) | psi | 20-80 psi |
Capacity & Maintenance(1) | ||
Filter Life (gallons) | 12 months gallons | 800 gallons |

Products in the top-left offer the best value (high score, low price).

Professional reviewers highlight the RO5DX's NSF/ANSI 58 certification as a key strength, validating its TDS reduction capabilities and material safety. While experts note that the certification does not cover the full range of 158 claimed contaminants, they consider TDS reduction the most important metric for RO systems.
Users generally praise the system for its reliable performance, compact size, and the peace of mind provided by NSF certification. The all-in-one kit format is appreciated for its convenience, and users report a noticeable improvement in water taste.




Search results contain no direct quotes from professional reviewers or editors. Product pages emphasize manufacturer claims regarding the 44% faster flow rate and the ability to filter 15 times more contaminants than leading pitcher filters, supported by WQA and NSF certifications.
Search results provide no user reviews, ratings, or testimonials. Walmart and Home Depot pages note items included and Q&A sections but no praise or complaints were extracted from user feedback.