Nalco 3688 -

While specific formulations are proprietary to Ecolab, Nalco 3688 is typically characterized by its combination of:

The product works by forming a microscopic protective film (passivation) on metal surfaces, which acts as a barrier between the aggressive cooling water and the system metal. nalco 3688

While less common, some spec sheets allow Nalco 3688 in closed loops where minor water loss occurs. It prevents initial corrosion of new systems or dormant components. While specific formulations are proprietary to Ecolab, Nalco

| Feature | Nalco 3688 | Traditional Chromate | Molybdate/Nitrite | All-Organic (no PO4) | |---------|------------|----------------------|-------------------|------------------------| | Corrosion control (mild steel) | Good (1-3 mpy) | Excellent (<0.5 mpy) | Excellent | Fair | | Yellow metal protection | Yes (azole) | No (requires additive) | Often lacks | Yes (if formulated) | | Scale inhibition | Excellent | Poor | Moderate | Very good | | Environmental compliance (P limits) | Moderate (P discharge) | Banned in many regions | Good (Low P) | Best (No P) | | Cost | Medium | Low (but illegal) | High | Medium-High | The product works by forming a microscopic protective

mpy = mils per year, a corrosion rate measurement.