Electrolysis Explained: How a Water Ionizer Makes Alkaline Water
Kamal, Founder of BelieveUpdated 10 Feb 20267 min read
Quick answer
A water ionizer passes clean water through a chamber of charged platinum-coated titanium plates separated by a membrane. At the negative plate (cathode), water molecules gain electrons and form hydrogen gas and hydroxide ions, making that stream alkaline and hydrogen-rich. At the positive plate (anode), water forms oxygen and hydrogen ions, making that stream acidic. The membrane keeps the two streams apart, so you get alkaline water from the tap and acidic water separately.
The two reactions
| Plate | Reaction (simplified) | Result |
|---|---|---|
| Cathode (−) | 2H₂O + 2e⁻ → H₂ + 2OH⁻ | Alkaline water + dissolved hydrogen |
| Anode (+) | 2H₂O → O₂ + 4H⁺ + 4e⁻ | Acidic water |
Hydroxide ions (OH⁻) raise the pH of the cathode stream. The hydrogen gas formed there dissolves into the water as tiny bubbles, which is what you see as a brief milky look in a fresh glass, and what drives the ORP negative.
Why minerals in the input water matter
Pure water conducts electricity poorly. The small amount of dissolved minerals in RO water (ideally 100–150 mg/L TDS) carries the current between the plates. Too little and electrolysis is weak; far too much and scale builds up on the plates.
What makes one ionizer stronger than another
- Plate area: more and larger plates mean more contact with water. Believe uses 11 platinum-coated titanium plates.
- Power supply: an SMPS keeps current stable even when household voltage fluctuates.
- Membrane quality: cleaner separation of alkaline and acidic streams.
- Flow rate: slower flow allows more electrolysis per litre (stronger settings).
- Cleaning: automatic reverse-polarity cleaning keeps plates free of scale.
Why the settings give different pH levels
Each setting changes how much current flows through the plates and how fast water passes through. More current per litre gives a higher pH and more hydrogen. That is how one machine offers Alkaline 1, 2 and 3, plus purified and acidic water.
Key takeaways
- Cathode (−): makes alkaline water with dissolved hydrogen.
- Anode (+): makes acidic water used for cleaning.
- The membrane keeps the two streams separate.
- More plate area and stable power mean stronger, steadier output.
Frequently asked questions
Is electrolysed water safe to drink?
The alkaline stream from a properly installed ionizer, at drinking settings (pH 8.5–9.5), is meant for drinking. The acidic stream is for external cleaning only.
Does an ionizer purify water?
No. It changes pH, ORP and hydrogen. Purification is the job of your RO, which is why Believe connects after it.
