My Water Filter’s Buyers Guide to Reverse Osmosis Water Filters [VIDEO]

In this article we are going to look at four of the most popular types of Reverse Osmosis Water Filters. The most important thing to consider when it comes to Reverse Osmosis systems is what it does to the water AFTER the membrane.

RO systems will remove fluoride, lead, chlorine and chloramine, pesticides, nitrates and sulfates, detergents and more.

Reverse Osmosis Water Filter - How Does It Work?

Before we talk about specific products it might help to explain briefly how Reverse Osmosis works. Reverse Osmosis differs from traditional water filtration where impurities are stored within the cartridge. Once the water is pushed through a series of filters, the clean water goes into a holding tank, and the contaminants are flushed down the drain.

Stage 1: Sediment Cartridge.

The water comes from the tap, enters the sediment cartridge which removes sediment and other matters like dirt and silt. This improves the taste and appearance of the water. This initial process is important to protect the carbon filter in the second stage.

Stage 2: Carbon Cartridge.

The second stage is to eliminate chlorine and chlorine compounds. It also removes other particles in the sediment filter like VOCs. The carbon filter is also effective at removing odors. The carbon stage conditions the water before the start of the reverse osmosis and helps protect the RO membrane against corrosion by removing chloride.

Stage 3: Reverse Osmosis Membrane.

It is the RO membrane that is the heart & soul of any RO system. The RO membrane splits the water into clean water and wastewater, sending the contaminants to waste and the clean water to your tap.

This is where Reverse Osmosis membrane filters out organic and inorganic compounds such as fluoride and heavy metals. This stage will also completely strip the water from Total Dissolved Solids (TDS) like sodium, calcium, magnesium will be reduced.

Stage 4: Carbon Post Filtration.

The final stage in the RO process is usually a carbon post-filtration phase that will remove any remaining aesthetic taste or odors, a “polishing stage”, for lack of a better word.

The Challenge After The Reverse Osmosis Membrane

Once the water has undergone Reverse Osmosis, we are left with ACIDIC WATER.

The pH after RO is about 6 pH. You don’t want to be drinking it yet!

We want water to be at 7 pH before drinking. Drinking water below 7pH carries the risk of stripping the mineral out of your body to keep your body at a healthy pH level.

All of the below systems will go through all 4 stages of reverse osmosis treatment. The difference between each system will be what happens after the RO membrane.

Benchtop Reverse Osmosis


The RO4000 will treat the water and strip everything out until it’s clean but it doesn’t remineralise the water again.

Since all the minerals have been removed from the water, the pH level of the water as the water flows out will be quite acidic with a pH level around 6 pH.

RO4000 With Alkaliser

The RO4000 will treat the water effectively, getting it to a pH of 6. Then, as the water flows through the Alkaliser cartridge, the water will dissolve & absorb the mineral it requires. This elevates the pH levels of your water while increasing its quality. The pH reading with a new alkaliser will be up to 9.5 pH then as the system is used the alkaliser will wear down over time and can be replaced when required.

Under Sink Reverse Osmosis Water Filters

Aquasana OptimH2O Reverse Osmosis Water Filter System with Claryum Technology & Remineralisation.

The OptimH2O pairs powerful reverse osmosis filtration with Claryum selective filtration PLUS remineralization.

It will treat the water effectively, getting it to a pH of 6, then it goes through a process to put some of those minerals back.

The Re-Mineraliser uses a dual media called calcite and Magflow. As the water passes from the holding tank to the stage 3 filter, potassium is added to the water through the potassium Ion exchange process. Next the water passes through the remineralizer and will pull only the mineral content it needs in order to stabilize the pH of the water. The minerals it pulls are magnesium and calcium.

The remineralizer isn’t a pH enhancer, It’s a pH stabilizer!

So at the very end, you’ll have water coming out of your faucet which is at a pH of 7 - which is how water should be.

The HPF 7 Stage Reverse Osmosis Under Sink Water Filter System.

The 7 Stage Hydrogen Rich Reverse Osmosis Filter has been designed and honed over a decade to produce the perfect drinking water to aid in hydration, combat illnesses and help the body recover and function as nature intended.

This 7 stage reverse osmosis water filter is an alkaline system, meaning that the pH of the drinking water produced by this system will be between 8.5 – 9.0 which is regarded as the optimal pH for alkaline drinking water.

After the 4 traditional stages of Reverse Osmosis, removing all chemicals and disinfectants from the water, the next important stage is FAR Infrared treatment.

The FAR Emitting ceramic beads act in a similar way to ultraviolet sanitation. They use infrared energy to keep the water free of bacteria and viruses and prolong the storage life of the filtered water.

FAR Infrared treatment goes hand-in-hand with negative magnetic treatment. It promotes chemical changes in the water to produce weak levels of peroxide, which quickly reacts in the high alkaline water to produce water and an additional oxygen molecule. This is where the increased dissolved oxygen content is introduced to the final stage of drinking water.

In this final stage, the water goes through the coconut carbon cartridge to polish up the taste of the water & finally through the negative magnet ready to drink.

Our Recommendations:

To help with the RO water system decision, first work out whether you require an under sink or benchtop system.

If you require a Benchtop System for drinking, we recommend an RO 4000 Benchtop Reverse Osmosis Water Filter System with Standard Alkaline. You’ll get great tasting water with high alkalinity.

If you require an Under Sink System, and you are looking for pH 7 with healthy minerals, we recommend the Aquasana, If you want to high alkalinity, we recommend a HPF 7 Stage Reverse Osmosis Under Sink Water Filter System. Both options create really amazing water.

Still Have Questions?

If by now you still haven’t decided which option is best for you, please talk to our support team. We’d be delighted to help!

Click here to see our full collection of Reverse Osmosis systems.

Category-reverse osmosis water filter systemsType-buyers guide