Best NU Aqua Reverse Osmosis Systems with Alkaline Filter in 2026: 2 Picks
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
Finding the best NU Aqua reverse osmosis systems with alkaline filter requires comparing published specifications. We analyzed 2 models to help you choose based on data, not opinions. The NU Aqua 6-Stage Alkaline RO System leads this list. It achieves high flow rates suitable for standard under-sink kitchens. Its six-stage filtration prioritizes output speed and mineral balance. This guide helps you decide which unit fits your cabinet space and water needs. You can compare dimensions and stage counts to find the right fit for your home.
Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | NU Aqua 6-Stage Alkaline RO System Best overall | High-flow alkaline water needs | Check price of NU Aqua 6-Stage Alkaline RO System on Amazon |
| 2 | NU Aqua 600 GPD Tankless RO Best budget | high-output tankless under-sink filtration | Check price of NU Aqua 600 GPD Tankless RO on Amazon |
The best fit for you
- You prioritize output speed and alkaline benefits NU Aqua 6-Stage Alkaline RO System The 6-stage alkaline filter delivers high flow for standard under-sink kitchens.
- You need efficient space-saving filtration for heavy use NU Aqua 600 GPD Tankless RO Its tankless 5-stage design with UV filtration fits tight cabinets and provides high output.
- You want white colored units for clean aesthetics NU Aqua 6-Stage Alkaline RO System This model features a white finish that blends well with standard kitchen cabinetry.
Our 2 picks
NU Aqua 6-Stage Alkaline RO System
Best for: High-flow alkaline water needs
- Features
- Alkaline Filter, Remineralization (what this guide is about)
- Filtration Stages
- 6
- Capacity (GPD)
- 100 GPD
- Design
- Under sink
- Certification
- NSF
- Filtration Type
- Reverse osmosis, alkaline
View on Amazon: NU Aqua 6-Stage Alkaline RO System Affiliate link
This NU Aqua system offers 100 GPD output with six filtration stages, including an alkaline filter for remineralization. It features quick-connect fittings and a stainless steel faucet. The unit measures 18 inches high and weighs 28 pounds. It includes a PPM meter for testing. This setup suits you if you want high flow and balanced mineral content in your drinking water.
Pros
- 100 GPD high flow rate
- Six-stage filtration with alkaline filter
- Quick-connect fittings for easy installation
- Includes complimentary PPM meter
Cons
- Requires under-sink storage space
- 28-pound weight needs sturdy support
- No built-in water quality display
Good fit if
- You need a high-flow under-sink system
- You want remineralized alkaline water
- You prefer quick-connect fittings
Skip if
- You need a tankless design
- You want a countertop unit
- You require UV sterilization
Verdict: NU Aqua 6-Stage Alkaline RO System delivers high flow and mineral balance for standard under-sink kitchens. It fits you if you prioritize output speed and alkaline benefits over tankless convenience.
NU Aqua 600 GPD Tankless RO
Best for: high-output tankless under-sink filtration
- Features
- Alkaline Filter, UV Filtration, Remineralization (what this guide is about)
- Filtration Stages
- 5
- Capacity (GPD)
- 600 GPD
- Design
- Tankless, under sink
- Pure to Drain Ratio
- 2:1
- Filtration Type
- Reverse osmosis, alkaline, UV
View on Amazon: NU Aqua 600 GPD Tankless RO Affiliate link
This NU Aqua unit is a tankless reverse osmosis system with five filtration stages. It includes an alkaline filter and UV-C light for added protection. The system delivers 600 gallons per day with a 2:1 pure-to-waste ratio. Its slim design fits under most sinks. The LED faucet indicates filter status. It suits you if you want high output without a storage tank.
Pros
- Tankless design saves under-sink space
- 600 GPD output capacity
- 2:1 pure to waste water ratio
- Five-stage filtration with alkaline and UV-C
- LED faucet shows filter life
Cons
- 25-pound weight requires sturdy mounting
- No storage tank for backup supply
- Limited to single faucet installation
Good fit if
- You need high daily water volume
- You want to save cabinet space
- You prefer direct-flow filtration
Skip if
- You require a storage tank
- You need multiple faucet outputs
- You have limited under-sink weight support
Verdict: NU Aqua 600 GPD Tankless RO with Alkaline offers efficient, space-saving filtration for households needing high water output. It fits best in kitchens where cabinet space is tight and daily usage is heavy.
Specifications side by side
| Spec | NU Aqua 6-Stage Alkaline RO System | NU Aqua 600 GPD Tankless RO |
|---|---|---|
| Filtration Stages | 6 | 5 |
| Capacity (GPD) | 100 GPD | 600 GPD |
| Design | Under sink | Tankless, under sink |
| Pure to Drain Ratio | not stated | 2:1 |
| Certification | NSF | not stated |
| Filtration Type | Reverse osmosis, alkaline | Reverse osmosis, alkaline, UV |
| Contaminants Removed | not stated | Sediment, rust, chlorine, VOCs, PFAS |
| Installation Type | Under sink | Under sink |
| Features | not stated | LED smart faucet, remineralization |
| Capacity | 100 GPD | 600 GPD |
| Use | Kitchen | not stated |
| Color | White | White |
| Dimensions | 15 × 5.5 × 18 inches | 15.5 × 5.5 × 13.5 inches |
| Weight | 28 pounds | 25 pounds |
| Size | RO - Stage 6 Alkaline | 5 Stage UV + Alkaline Tankless RO |
| Model | WU-100GPD-NP-ALK | KF-600GPD-UV-ALK-2FTL |
Choosing Your NU Aqua Alkaline RO System
-
Check physical dimensions
Measure your under-sink cabinet space before buying. The NU Aqua 6-Stage Alkaline RO System measures 18 inches in height and weighs 28 pounds. This tanked model requires more vertical clearance. The Tankless 600 GPD model is shorter at 13.5 inches high. It also weighs less at 25 pounds. Verify your available width and length match the unit's footprint. Ensure you have room for the storage tank if you choose the 6-stage option. Proper sizing prevents installation headaches later.
-
Compare filtration stages
Review the number of filtration stages for your water quality needs. The 6-Stage Alkaline RO System includes six distinct layers of filtration. This setup targets a broader range of contaminants before the final alkaline boost. The Tankless 600 GPD model uses a 5-stage process. It integrates UV filtration into the fifth stage. Choose the 6-stage model if you prefer traditional multi-stage purification. Select the 5-stage UV model if you want added disinfection without a storage tank. Both include the alkaline filter for mineral balance.
-
Assess daily capacity
Determine your household's daily water consumption. The 6-Stage Alkaline RO System produces 100 gallons per day. It stores this water in a tank for immediate use. This suits families with moderate drinking and cooking needs. The Tankless 600 GPD model generates 600 gallons per day. It provides water on demand without a tank. This high output is ideal for large households or heavy usage. Match the capacity to your peak usage times. Higher gallons per day ensures you never run dry during busy periods.
-
Evaluate design type
Decide between a tanked or tankless design. The 6-Stage Alkaline RO System uses a traditional tanked approach. This design ensures consistent pressure and immediate availability. The Tankless 600 GPD model eliminates the storage tank. This saves cabinet space and prevents stale water storage. It also reduces the risk of bacterial growth in the tank. Choose the tanked model for reliable, stored supply. Pick the tankless model for space efficiency and fresh water on demand. Your choice affects both installation complexity and long-term maintenance.
-
Review special features
Look for additional filtration technologies beyond standard RO. The Tankless 600 GPD model includes UV filtration. This feature adds a layer of disinfection against bacteria and viruses. The 6-Stage Alkaline RO System focuses on mechanical and chemical filtration. It relies on the alkaline filter for pH adjustment. If you want extra protection against microbes, the UV feature is valuable. If you prefer a simpler mechanical process, the 6-stage setup suffices. Both models include the alkaline filter to improve taste and mineral content.
Frequently asked questions
Does the NU Aqua 600 GPD Tankless RO use UV light?
Yes, this model includes UV filtration as a core feature. It combines a 5-stage process with ultraviolet treatment to reduce contaminants. The tankless design ensures you get fresh water on demand without stored reserves. This setup suits households with tight cabinet spaces who need high daily output.
Which NU Aqua RO system is best for high flow rates?
The NU Aqua 600 GPD Tankless RO delivers the highest output. It produces 600 gallons per day without a storage tank. This makes it ideal for heavy daily usage. The 6-Stage Alkaline RO System offers 100 gallons per day with a tank, which is slower but sufficient for standard kitchens.
What is the difference between the 5-stage and 6-stage models?
The 6-stage model adds an alkaline filter to the final stage for mineral balance. The 5-stage tankless model includes UV filtration instead of the extra alkaline stage. Both provide under-sink installation. Choose the 6-stage for mineral enhancement and the 5-stage for space-saving tankless operation with ultraviolet purification.
How much space does the NU Aqua 6-Stage Alkaline RO System take?
This tanked system measures 18 inches in height, 15 inches in length, and 5.5 inches in width. It weighs 28 pounds. The included storage tank requires additional vertical clearance in your under-sink cabinet. Ensure you have enough room for both the unit and the tank before purchasing.
Is the NU Aqua 600 GPD Tankless RO suitable for small cabinets?
Yes, its compact dimensions make it ideal for tight spaces. It measures 13.5 inches in height and 15.5 inches in length. The tankless design eliminates the need for a large storage tank. This saves significant under-sink space while still providing high daily water output for your household.
Do these NU Aqua systems come in white?
Yes, both the 6-Stage Alkaline RO System and the 600 GPD Tankless RO are white. This neutral color helps them blend into most kitchen under-sink environments. The visual consistency allows for a clean look regardless of which filtration stage or tankless design you choose for your home.