Reverse osmosis (RO) systems are incredibly effective at removing contaminants from drinking water. Unfortunately, because of the tiny pore sizes in the RO membrane, they also remove beneficial minerals like calcium and magnesium.
Naturally, this poses many questions.
How are the minerals removed? Is it possible to stop them being removed? Can they be reintroduced? The short answer is yes.
In this guide, we will answer all of these questions in detail. We will also give you some RO alternatives that don’t remove beneficial minerals from water.
Which Healthy Minerals Does Reverse Osmosis Remove?
The table below contains the most common minerals found in water and their benefits.
The reverse osmosis process removes all of these minerals.
Mineral | Benefits |
---|---|
Calcium | Maintains the taste and hardness of the water. Essential for bone and teeth development |
Magnesium | Supports weight management, plays a key role in food-to-energy conversion |
Potassium | Balances body fluid, supports complex body organs |
Phosphorus | Helps in bone and tooth formation |
Sodium | Adds alkaline taste to the water, balances water and mineral levels in the body |
Copper | Important for brain function, connective tissue formation, and energy production |
Zinc | Boosts the immune system and helps in blood function |
How Are Minerals Removed During the RO Process?
Reverse osmosis systems feature a unique RO membrane with tiny pores of 0.0001 microns. The size of dissolved components in water ranges from 5 microns to 1 micron. This means that RO filters are really effective at removing almost all of these particles. This includes harmful contaminants but also beneficial minerals.
Here’s how the reverse osmosis process works:
- A RO system reverses the osmosis process (the natural tendency of water to flow towards higher salt concentrations) using a powerful pump. Inside the RO system, the pump forces water through multiple filters to separate the impurities and dissolved components.
- Usually, most reverse systems have three filtering cartridges. The first one is a sediment filter that separates larger contaminants. As most mineral molecules have a diameter of 1 micron or less, this filter doesn’t separate healthy minerals from unhealthy minerals.
- The second filter is an activated carbon filter that removes thinner particles like lead, chlorine chemicals, etc.
- Then, the water passes through the last and most effective filter, the semi-permeable RO membrane. While other regular filters only separate molecules up to 1 micron in diameter, the RO membrane can remove molecules as small as 0.0001 microns! This means the tiny pores of the RO membrane filter out most minerals (including beneficial ones) during the RO process.
Is It Possible to Stop The Removal of Minerals?
Yes, it's possible to stop the removal of minerals if you separate the RO membrane from the reverse osmosis system itself. However, you must remember that the reverse osmosis system will become like any regular water purifier without this special filter. The sediment and carbon filters can only remove contaminants as small as 5 microns.
This means microscopic viruses and some harmful contaminants won't be filtered from the water. If you are ready to discount this health risk, you can remove the reverse osmosis membrane to maintain the optimum amount of essential minerals in filtered water.
Can the Minerals Be Reintroduced?
Many modern reverse osmosis systems are able to reintroduce beneficial minerals to water once the filtration process has been completed.
Some include an alkaline filter to add a measured amount of healthy minerals to the water, and this filter also slightly raises the water’s pH level.
If your RO system doesn’t have an alkaline filter, you can manually reintroduce beneficial minerals to the water using mineral drops. However, we think adding an alkaline filter to your system is the better long-term solution.
This is because an alkaline filter automates the process of mineral reintroduction, which is much more convenient than using drops. Plus, it’s much harder to reintroduce minerals at a consistent level with drops, as you can easily add too much or too little.
Are There Reverse Osmosis Alternatives That Does Not Remove Minerals?
If you’re concerned about beneficial minerals being removed during the RO process, you may want to consider an alternative filtration method that retains them. Let’s take a look at 4 of the best RO alternatives:
1. Biocompatible Water Filtration
Biocompatible water filtration is a 7-stage process that uses a combination of technologies like mechanical filtration and activated carbon to remove contaminants while leaving healthy minerals behind. The process involves several stages of filtration.
However, the process and the tech used can vary between makes and models. Some biocompatible systems include an RO stage, which means that beneficial minerals are still removed from the water. So, it’s important you do your research before purchasing a biocompatible system.
2. Ultrafiltration
Ultrafiltration is effective at disinfecting tap water without eliminating minerals. It removes 99.9% of bacteria, protozoa, and viruses from water. Another benefit is that it produces no wastewater and runs without electricity.
The main downside of ultrafiltration is that it typically doesn’t remove certain impurities like pesticides or heavy metals. If these contaminants are present in your water supply, you’ll need to install a pre-filter alongside the ultrafiltration system.
3. Carbon Block Filtration
Carbon block and activated carbon filtration are highly effective at eliminating industrial chemicals, pesticides, and herbicides.
These filters remove pathogens, chlorine, toxins, heavy metals, and other contaminants from water. However, carbon filters aren’t as effective as reverse osmosis, and you’ll need a filter attachment to remove fluoride from tap water.
Yet, carbon filters are usually more affordable than RO systems and they don’t remove as many beneficial minerals, which means they can be a great alternative.
4. Ceramic Filtration
Another low-cost purifier option that retains minerals in refined water is a ceramic filtration system. It can effectively eliminate bacteria and protozoa from water. Ceramic filters have also been proven helpful in reducing diarrhea-causing pathogens. However, they don’t remove chlorine and some microscopic viruses.
Ceramic filtration systems also tend to be less expensive than RO filters, and they retain beneficial minerals in water. However, ceramic filters are often unable to remove chlorine, heavy metals, pesticides, and some microscopic viruses. If this is a concern, you could consider adding an activated carbon pre-filter to your ceramic system.