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Frizzlife PX500-A Tankless Reverse Osmosis Filter Review

Frizzlife PX500-A Reverse Osmosis Water Filtration System
Frizzlife PX500-A Undersink Tankless RO System

The Frizzlife PX500-A is an exciting new tankless under sink reverse osmosis water filtration system that scores well in our rankings of both tankless RO systems and all undersink RO systems.

This system has a high throughput of 500 gallons per day (GPD) and 7 stages of water filtration, including an alkaline remineralization stage and a great wastewater ratio.

Plus, since this system is tankless, it is smaller and easy to maintain under your sink.

System Design


The pressurized water storage tank and exposed system components of traditional RO systems are replaced by a sleek housing with a compact, integrated system that takes up 60% less space.

To power the internal pump that provides water pressure without a storage tank, the PX500-A system needs an electrical outlet (100-240v).

Because there is no storage tank, the system case takes up just a little of the available space under your sink. Furthermore, access to changeable filters is readily available on the front side of the case, making filter replacements quick and simple.

The PX500-A has a processing capacity of 500 gallons per day and a fantastic ratio 1 gallon of waste water for every 1.5 gallons of filtered water (1.5:1). This is almost as good as an RO system can do and far superior to other systems on the market.


Here we review the PX500-A version of the standard PX500. The difference is that the PX500 has an advanced activated carbon filter for the 3rd stage, while this PX500-A has a combination activated carbon AND remineralization filter for the 3rd stage.

Frizzlife alkaline remineralization

The purpose of a remineralization stage is to add some of the natural and beneficial trace minerals back to the water after is has been filtered. Keep in mind that these minerals will raise the TDS (Total Dissolved Solids) reading of the output water.

The reverse osmosis (RO) membrane is so efficient that it removes any minerals in the source water, lowering the pH of the filtered water and making it more acidic.

When the remineralization stage adds these minerals back, the pH is raised into the alkaline range (7.5 or higher), which is considered healthier. This also gives the water a more smooth, mineral water taste.

While other tankless RO systems offer a remineralization stage, it is usually a separate unit that must be installed along the water line. This is the only system that integrates the alkaline remineralization stage in the main system chassis.

Integrated Pump

The integrated, powered pump in this system ensures ideal water pressure at all times, regardless of the water pressure in your plumbing.

In our tests, you can fill a cup of water in about 12 seconds with this system, even without a storage tank.

It is normal for a brief drop in pressure from the faucet with a tankless RO system immediately after it is turned on. However, because of the pump, this system will continue to produce pure water a steady pace. Compare this to an RO system with a tank, which will see a dramatic drop in pressure after the storage tank is emptied.

Easy Maintenance

In a traditional RO system, you must shut off the water supply, drain the system, and then remove the filters or filter housing at awkward angles under your sink. Tankless systems, such as the Frizzlife PX500-A, feature filters that are accessible from the front of the device.

Frizzlife PX500-A LED indicators

Smart filter life indicators indicate when a filter is nearing end-of-life or has passed its replacement date. When the filter’s remaining percentage is less than 5%, the indicator light will blink red. The indicator light will stay red, and an audible buzzer can be heard if there is 0% left on the filter.

To replace a filter:

  • Power off the system
  • Turn on the RO faucet to drain water
  • Remove the system faceplate by pulling on the bottom edge
  • Twist out the old filter
  • Twist in the new filter
  • Turn the power back on
  • Reset the filter as indicated in the owner’s manual

Of the three filter cartridges used by the Frizzlife PX500-A, one should be replaced every 6 months, one should be changed once per year and the third needs to be replaced once every two years. We provide links to the necessary replacement filters at the bottom of this page.


The dedicated filtered water faucet must have a hole in your sink or countertop for the undersink reverse osmosis system.

Aside from that, the setup and installation of the Frizzlife PX500-A is extremely simple and straightforward. It may be installed in less than an hour by anyone with basic DIY skills and tools.

The installation guide and related videos explain everything.

PX500-A Pros

  • Compact, tankless design
  • Integrated alkaline filter to remineralize the water
  • Filters come pre-installed and connections are easy to reach
  • Easy to follow instructions and installation video
  • Daily throughput of 500 GPD
  • Very good wastewater ratio
  • Alternative black faucet is available from Frizzlife
Frizzlife PX500-A installed under sink

PX500-A Cons

The PX500-A is a great system but could be even better.

  • Filters can be hard to twist in and out
  • The system can be noisy when processing water
  • No smart faucet with filter life indicators
  • All tankless RO systems need help to power an ice maker, but Frizzlife offers the Mini Tank (described below) to solve this problem.


Frizzlife PX500-A unboxing

Frizzlife makes a really nice collection of undersink and countertop reverse osmosis filters.

If you’re looking for a small, simple to operate tankless system with smart functions and an alkaline remineralization filter built into the chassis, this is the one to get.

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Our top-rated accessories for this or any other RO system will help you customize your installation!

Frizzlife PX500-A Replacement Filters

You can refer back here to order replacement filters as necessary.  It may help to order your Stage 1 and 3 filters now, so you are ready when the filter indicator light turns on in about 12 months.

The Frizzlife PX500-A system will show an indicator light on the front faceplate when a filter is nearing its end of life. That is the time to come back here and order the necessary replacement filter.

Black RO Faucet

If you prefer a black RO faucet to match your existing kitchen faucet or decor, Frizzlife offers their stainless steel faucet in a matte black finish.

A brushed nickel faucet is included with the RO filtration system and the black faucet must be ordered separately.

Frizzlife ST-3B Black Drinking Water Faucet

Frizzlife Mini Water Tank for Reverse Osmosis Systems

Frizzlife makes the model MWT3 mini water tank to help solve one of the only problems associated with tankless RO systems… lack of pressure for a refrigerator or ice maker connection.

Frizzlife Mini Tank
Frizzlife Mini Water Tank

If you have a water dispenser or ice maker in your refrigerator, it makes sense to use the same pure, clean filtered water from your RO system to feed these devices.

It’s easy to run an extra water hose from your RO system to the fridge, but tankless RO systems usually don’t provide high enough water pressure over long distances or for the short time an ice maker draws water.

The Frizzlife Mini Water tank solves this problem.

Install this between your RO system and the refrigerator to maintain a higher level of water pressure and help with ice makers and water dispensers.

This mini tank works with ANY RO system and can be used to improve the water pressure on your existing tankless reverse osmosis water filter.

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