pH BUFFER 4 300ML

Description

pH Buffer 4 300ml is a precision calibration solution used to accurately set your pH meter or probe to the 4.01 reference point, ensuring that all subsequent pH measurements in your nutrient solution and growing media are reliable and traceable. We have been recommending regular pH meter calibration to UK growers since 2017 as one of the most important maintenance habits for consistent, high-performance growing — an uncalibrated pH meter is arguably more dangerous than no meter at all, because it gives you false confidence in measurements that are directing your feeding decisions.

Why Calibrating Your pH Meter Matters So Much

pH meters and probes drift over time as a result of electrode aging, contamination from nutrient solutions, and exposure to cleaning agents. A probe that was accurate six months ago may now read 0.3–0.5 pH units higher or lower than the true value. In hydroponics, where the window between optimal pH (5.8–6.2) and lockout (below 5.5 or above 6.8) is narrow, a drift of even 0.3 pH units can place your solution in a range where one or more nutrients become unavailable to plants — leading to deficiency symptoms that appear unrelated to pH because your meter is telling you everything is fine. pH Buffer 4 is a reference solution with a precise and certified pH of 4.01 at 20°C, which combined with a pH 7 buffer allows your meter to be calibrated accurately across the full range you use in hydroponics. The 300ml bottle provides enough calibration solution for dozens of calibration sessions.

How to Use pH Buffer 4 for Accurate Calibration

Pour a small amount of pH Buffer 4 into a clean container — never dip your probe directly into the bottle. Rinse the probe with distilled water and dry gently before dipping into the buffer solution. Allow the reading to stabilise, then adjust the meter’s calibration offset to read exactly 4.01. Rinse the probe again with distilled water before proceeding to calibrate at pH 7 using the corresponding buffer solution. Calibrate your meter at minimum every two weeks during active grows, or before any critical measurement. Always use fresh buffer solution and discard used portions — never return used buffer to the bottle.

Pair pH Buffer 4 with pH Buffer 7, a quality digital pH meter, and pH Up and Down solutions for a complete pH management setup. Browse our full range of pH and EC meters, calibration solutions, and measurement accessories.