Reverse Osmosis vs. Alkaline Water: Can Water Be "Too Pure"?

You’ve just installed a high-end Reverse Osmosis (RO) system, and the TDS meter proudly reads “2 ppm.” You’ve successfully removed 99.99% of all contaminants. But when you take a sip, you’re… underwhelmed. As one new RO user perfectly described it, the water tastes “quite ‘empty’.”

This experience is the heart of a long-running debate: Can water be too pure?

This confusion pits two giant marketing forces against each other: the RO Purity camp (which preaches removing everything) and the Alkaline Mineral camp (which preaches adding things).

The RO Dilemma: Does “Purity” Mean “Unhealthy”?

The core criticism of RO filtration is that, in removing the “bad” contaminants (PFAS, lead, arsenic), it also removes the “good” beneficial minerals (calcium, magnesium, potassium).

This is 100% true. The 0.0001μm membrane is a non-discriminating sieve; it removes it all. This leads to two concerns:
1. Taste: As we’ve noted, the water tastes flat or “empty” because minerals provide the flavor we’re used to.
2. Health: Does removing these minerals make the water unhealthy or “acidic”?

This is where context is critical. According to the World Health Organization (WHO), the vast majority of essential minerals our bodies need come from food, not water. While water can contribute, you are not risking a mineral deficiency by drinking pure RO water, provided you eat a balanced diet.

The “acidic” claim is also minor; RO water can have a slightly acidic pH simply due to its interaction with CO2 in the air, but it’s not a health risk.

The Alkaline Solution: More About Taste Than Magic

This brings us to “alkaline” or “remineralization” filters. These are designed to “fix” RO water.

They work by passing the pure RO water through a filter cartridge containing mineral media. * What it does: It adds back “good” TDS, specifically calcium and magnesium. * The Benefit (Taste): This is the most significant, undeniable benefit. It solves the “empty” taste problem, creating water that is often described as “crisp,” “smooth,” and “refreshing.” * The Benefit (pH): By adding these alkaline minerals, it neutralizes the water’s pH, bringing it from slightly acidic (pH ~6.5) to neutral (pH 7) or slightly alkaline (pH 7.5+).

While proponents may claim other health benefits, the most tangible, science-backed advantages are the dramatic improvement in taste and the neutralization of pH.

The Best of Both Worlds: Purify Then Optimize

The debate isn’t about choosing RO or Alkaline. The ideal process is to use them together.
1. Purify (RO): Use Reverse Osmosis as the engine for purification. This is your non-negotiable step to create a “blank slate” by removing dangerous, invisible contaminants like PFAS and heavy metals.
2. Optimize (Alkaline): Use a remineralization filter as the finishing step to “build” your perfect drinking water, adding back beneficial minerals for taste and pH balance.

A Case Study in Choice: The Stokk T1

This “purify then optimize” philosophy is perfectly embodied in the design of some modern countertop systems. The Stokk T1, for example, isn’t just an RO filter or an Alkaline filter; it’s both, in a way that allows the user to choose.

• It dispenses pure RO water (the “2 ppm” water) directly from its main faucet.
• It also comes with a separate alkaline mineral boost carafe.

This brilliant design gives you two types of water from one machine:
1. Pure RO Water (Low TDS): Use this for your coffee machine, humidifier, iron, or CPAP machine. Why? Because it has no minerals, it will never cause limescale buildup, extending the life of your appliances.
2. Alkaline Mineral Water (Higher TDS): Dispense the RO water into the carafe, let it mineralize, and use this water for drinking. It has the great taste and balanced pH.

This design ends the debate. You don’t have to choose. You get the purity of RO and the taste of mineral water, and you can use each for its ideal purpose.