pH Adjustment Chemical Dose Calculator

Work out ph adjustment chemical dose instantly with clear inputs, formula shown and shareable results.

About pH Adjustment Chemical Dose Calculator

pH adjustment dose depends far more on buffering capacity than on the pH change itself. A poorly buffered soft water shifts pH with a very small dose, while a highly alkaline water resists change. The dose must be established by titration on the actual water and verified by continuous pH monitoring.

Formula

Dose estimate

Dose (mg/L) proportional to pH change x buffering factor, with buffering factor = 1 + alkalinity / 50

Worked example

With the default values below, pH Adjustment Chemical Dose Calculator returns Chemical Required of 60.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Flow Rateminimum 0 m3/day: 5,000 m3/day
Current pHaccepts 0.1–14: 5.5
Target pHaccepts 0.1–14: 7.5
Buffering Alkalinityminimum 0 mg/L as CaCO3: 25 mg/L as CaCO3

Results

Chemical Required: 60.000
Estimated Dose: 12.000
Buffering Factor: 1.5000
Adjustment Direction: Raise pH with lime, caustic soda or soda ash

Step by step

1Values used
2Dose estimate
3Chemical Required= 60.000
4Estimated Dose= 12.000
5Buffering Factor= 1.5000
6Adjustment Direction= Raise pH with lime, caustic soda or soda ash

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
pH correction affects lead and copper release from plumbing and is a regulated corrosion control measure. Acid and caustic chemicals are hazardous and require containment and dosing safeguards.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

pH correction affects lead and copper release from plumbing and is a regulated corrosion control measure. Acid and caustic chemicals are hazardous and require containment and dosing safeguards.

Frequently Asked Questions

Why is pH corrected at all?

To control corrosion and metal release in the distribution system, to optimise coagulation and disinfection, and to meet the regulatory pH range. Under-corrected soft water dissolves lead and copper from plumbing.

What is the Langelier index?

A saturation index indicating whether water will deposit or dissolve calcium carbonate. Corrosion control aims for slightly positive saturation so a protective scale forms without excessive deposition.