Aquasana AQ-RO-3.55 OptimH2O RO System Review – Want a Tasty Water with the Essential Minerals?


OUR RATING: (4.5/5)

The biggest concern people have when it comes to reverse osmosis water filtration is the hanging question around drinking demineralized water. No matter where you turn to online you will find many people arguing it is detrimental towards our health and just as many arguing that it has little to no effect. In a perfect world, we should get all these minerals from our food supply, but busy as we are, that’s rarely the case.

What isn’t in doubt, however, is that our body needs these minerals for various functions and for general health. Whatever the source may be. It should then be with relief that you find out about a reverse osmosis water filtration system that replenishes the minerals lost during the reverse osmosis process. More specifically the Aquasana AQ-RO-3.55 OptimH2O Reverse Osmosis Fluoride water filter.

Let’s look at this system in more detail and review it for you so you can make the best decision for you.


NSF/ANSI Standards 42, 53 & 58

Standard 42 means it’s certified to remove particles that make your water taste or smell. Standard 53 means that it’s certified to filter out contaminants that have negative health impacts. Standard 58 ensures that it’s actually a reverse osmosis water filtration system.


3-stage filtration system

Like any reverse osmosis water filtration system the Aquasana AQ-RO-3.55 has 3 stages of filtration.



This system replenishes essential and healthy minerals that are lost during reverse osmosis.


2-gallon storage tank

3.2 Gallons is not the biggest but adequate for a family’s daily drinking water needs.


4 faucet styles

Choose the look and feel that suits the rest of your home and satisfies your taste. You can choose from brushed nickel, chrome, oil rubbed bronze, and chrome metal.


5 gpm flow rate

While this definitely isn’t the fastest on the market it should just be enough if you let your system fill up over night.

Pros and Cons


Remineralization neutralises the only negative to a reverse osmosis system.


Better PH balance leads to a better taste.


Reduces much more fluoride and other substances than most other systems.


It runs a bit slow compared to other systems. Many buyers state it isn’t as fast as Aquasana claim.


It only produces 17.91% of the water that’s filtered which isn’t very efficient.

AQUASANA AQ-RO-3.55 – How Does It Work?

If you read our blog post, How does Reverse Osmosis work, you would know that most reverse osmosis water filtration systems make use of a 3 stage process.

Each stage filters out different contaminants and the end result is pure, crystal clear drinking water. The only problem is you lose many healthy minerals too.

This is how the Aquasana goes about the process of remineralizing your drinking water after reverse osmosis:

The 4-Stage System


First of all, the water goes through the AQ-RO3 Carbon filter that removes carbon and chlorides. These largely contribute to the bad taste or odor of water.


The Aquasana has a special stage 3 with the trademark Claryum filter which removes an additional 60 contaminants. Including pesticides and herbicides.


This is the main stage of any reverse osmosis system, where the water passes through the RO membrane. This is where most contaminants and particles are removed. Aquasana guarantees the removal of 14 contaminants with their RO membrane. Including fluoride, nitrates, lead, and arsenic.


Now, we get to the Aquasana’s star feature. The water remineralization. This is done through a special remineralizer that replenishes calcium, magnesium, and potassium. The addition of these minerals also makes the water more PH balanced by reducing acidity which improves the taste as well.

So, What’s Our Impression?

Well, first of all, it’s hard to say exactly how big a difference the remineralizer makes to your health. This topic is still up for debate. However, we can say that you definitely taste the difference. The water is definitely less acidic and has that almost (but not really) sweet taste that is refreshing.

Although the machine definitely doesn’t run as fast as other competitors (even some we have reviewed). This shouldn’t cause you too much grief if you don’t empty the storage tank in a single day. Maybe it would have been nice if this specific system had a slightly bigger storage tank.

All in all though, it’s still a very good reverse osmosis water filtration system and the remineralization isn’t just some sales gimmick, you really taste the difference. Whether, it’s really more beneficial for your health is debatable, but it definitely couldn’t hurt.

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