pH Drift

Definition

A shift in system pH, up or down, that changes scaling, corrosion, and biocide behavior simultaneously.

A high pH drift from acid feed failure or excessive CO2 stripping pushes carbonate equilibrium toward carbonate, raising calcium carbonate supersaturation and LSI while slowing general corrosion. The same drift weakens the oxidizing biocide species and can precipitate calcium phosphate, so a single pH move becomes a scale, bio-control, solids, and under-deposit corrosion problem at once. A low pH drift instead dissolves protective films and raises general corrosion and iron.

Related concepts

CO2 Stripping · Carbonate Equilibrium · Langelier Saturation Index

---

Part of The Blueprint of Water · 🧪 chemistry