HOCl Kill Power: Understanding Free Available Chlorine (FAC)
HOCl is powerful—but how do you measure that power? It all comes down to one metric: Free Available Chlorine, or FAC. This is the active disinfecting ingredient in your hypochlorous acid solution—and it determines how strong your kill power really is.
Understanding FAC gives you control over:
- 💧 Disinfection strength
- ⚖️ Regulatory compliance
- 📉 Chemical safety
- 🔬 System efficiency
What Is FAC?
FAC refers to the amount of free chlorine molecules (like HOCl and OCl⁻) available in your solution to kill microbes. It’s measured in ppm (parts per million) and fluctuates depending on:
- 🔄 Flow rate
- ⚡ Amperage
- 🧂 Additive type (salt + vinegar or HCl)
- 📉 pH level
The Perfect Range by Use Case
| Use Case | FAC (ppm) | Notes |
|---|---|---|
| Hands / Skin | 20–60 ppm | Gentle, pH-neutral |
| Produce / Food Surfaces | 50–100 ppm | No rinse required |
| Tools / Floors | 100–200 ppm | Spray or mop |
| Medical / Outbreak Control | 200–400 ppm | High-kill, fast acting |
EcoloxTech generators can produce up to 400 ppm FAC using Formula 3 (HCl) on the E-1200.
How to Measure FAC
You can easily measure FAC using:
-
Chlorine Test Strips
Measures 10, 50, 100, 200 ppm
-
Chlorine Photometer
Digital ppm measurement
Just dip and match—or scan the reading for ultra-precise ppm control.
How to Adjust Your HOCl System for Target FAC
EcoloxTech systems give you real-time control of FAC levels using three adjustable variables:
| Setting | Increases FAC When... |
|---|---|
| Ampere (A) | You raise it (more electrical current = stronger HOCl) |
| Pump Speed (PS) | You lower it (more concentrated brine enters cell) |
| Flow Rate (L/min) | You lower it (longer reaction time = more chlorine) |
Example (E-1200 at 22A):
- 1 L/min = ~278 ppm FAC
- 6 L/min = ~108 ppm FAC
pH and FAC: The Hidden Connection
HOCl is most active when pH is 5–6. Above pH 7, HOCl begins converting to hypochlorite (OCl⁻), which is less effective and more corrosive. You can maintain ideal pH by:
- Using Formula 2 or 3 in your additive tank (vinegar or HCl)
- Installing an EcoloxTech pH dosing system for automatic control
Optimize Your Kill Power
Knowing your FAC = knowing your sanitizing strength. With EcoloxTech:
- You can test it.
- You can control it.
- You can trust it.
