pH Testing & pH Color Chart

The pH of a substance is the measurement of the H+ions found in that particular substance.
pH is determined and recorded as a number between 0 and 14.
Neutral water has a pH of 7.0. A lower pH will dissolve metal.

Glycol fluid pH is primarily a function of the corrosion inhibitor, and therefore,will vary by product.
Most concentrated inhibited glycols have a pH in the 9.0 to 10.5 range.
When diluted in a 30% to 50% solution, the pH falls to between 8.3 and 9.0.

A pH reading below 8.0 indicates that a significant portion of the inhibitor
has been depleted and that more inhibitor needs to be added.

Recommended pH levels vary by boiler manufacturer - READ YOUR MANUAL

A pH level between 8.0 and 10.0 should provide the necessary corrosion protection.
Testing of pH level is best measured with a field pH meter, although commonly measured with
disposable pH test strips each strip will have its own color chart for determining pH.

The following color charts are provided as a guide.

If Printing or viewing this page remember that different monitor color settings and
different printers may cause the colors to look different.

pHydrion Papers (Hydrion 1-12) pH color chart
6 7 8 9 10 11 12

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Last modified: 04/18/15