Trust your pH readings againGrowth Technology Buffer 7 is a calibration solution with a stable, known value of pH 7.0, used to check and calibrate pH pens and meters so the numbers guiding your feeding decisions are actually accurate. It works with pH pens and meters from any brand, not just Growth Technology's own.Is your pH pen giving you readings you can't trust?An uncalibrated pH pen drifts over time, so you can end up dosing acid or alkali against a number that's wrong - and once nutrient pH is off, plants can't take up feed properly no matter how well it's mixed. Checking your pen regularly against Buffer 7's fixed pH 7.0 keeps that risk off the table.Key Benefits Stable reference pH 7.0: a fixed, known value for reliable pen calibration. Works with any brand: suitable for calibrating pH pens and meters regardless of manufacturer. Keeps feeding accurate: protects against nutrient-uptake problems caused by incorrect pH dosing. Simple, fast routine: a quick dip is all it takes to confirm your meter is honest. How to Use Rinse the electrode in clean water, then dip the pen into the Buffer 7 solution. Follow your meter's calibration procedure and adjust the reading until it matches pH 7.0. For best accuracy, calibrate at both pH 7.0 and pH 4.0 where your meter supports two-point calibration. Discard used solution afterwards - never pour it back into the bottle, as it will contaminate your stock.