Calibration fluid PH 7.01 100ml

A 100 ml bottle of pH 7.01 buffer. Enough for a season of regular calibration, rather than a sachet at a time.

This bottle holds the same liquid as the 20 ml sachets: a solution at a precisely known pH of 7.01, in a quantity that lasts you months.

Shelf life, and the mistake everyone makes

A bottle is better value per millilitre, but it comes with one thing sachets avoid: buffer solution has a limited life once opened.

A buffer's value is fixed because its composition is fixed. As soon as air reaches it, that composition slowly changes. Carbon dioxide from the air dissolves and shifts the acidity. A bottle that has stood half-open on a shelf for a year will calibrate your meter wrongly, with all the conviction of a precise figure.

Three habits that prevent it:

• Pour a little into a clean pot and calibrate in that. Never directly in the bottle.
• Never pour used solution back. Your tip always carries something with it, contaminating your whole supply.
• Keep the cap open briefly and write the opening date on the bottle.

Unsure whether an old bottle is still right? Replace it. A bottle of buffer costs less than a crop steered on a wrong number.

Technical Specifications:

• Value: pH 7.01
• Volume: 100 ml
• Use: first calibration point (zero point) on any pH meter

Frequently asked questions

How long does an opened bottle last?
It depends how often and how long it is opened. Keep it brief, note the date, and replace it if in doubt.

Bottle or sachets?
Calibrating monthly, a bottle is better value. Calibrating rarely, sachets are more practical because each one is fresh.

How should I store it?
Cool, dark and tightly closed. Not in a warm grow room.