Not all pH measurements are the same, which is why different buffer values are useful.

🔴 pH 4.00 Buffer Solution

The pH 4.00 solution provides an acidic reference point.

It is supplied as a clear red liquid, making it easy to distinguish visually from the pH 7.00 solution. The supplied SDS lists its pH as 4.00 at 20°C.

🟡 pH 7.00 Buffer Solution

The pH 7.00 solution provides a neutral reference point.

It is supplied as a clear yellow liquid, with a stated pH of 7.00 at 20°C.

Why have both?

Having different reference points allows users to select the appropriate buffer solution for their pH measurement requirements.

The colour-coded appearance also makes the two solutions easy to tell apart at a glance.

At a glance:

Two colours. Two reference points. One important purpose – supporting accurate pH measurement.