Growth Technology pH Buffer 4 — 300ml Calibration Solution

Growth Technology pH Buffer 4 — 300ml Acidic Calibration Solution

A stable pH 4.0 calibration fluid — the acidic reference point used alongside pH 7.0 buffer for two-point pH meter calibration. Particularly important for hydroponic growers whose nutrient solutions sit in the 5.5-6.5 range (closer to pH 4 than pH 7, so the 4-point calibration is more relevant than the 7-point for actual working readings).

Why growers need pH Buffer 4:

• Stable acidic pH 4.0 reference — essential second point for two-point meter calibration
• Particularly relevant for hydroponic use — working pH (5.5-6.5) is closer to 4 than to 7
• Pair with pH Buffer 7 — together give proper calibration across the usable range
• Works with any pH meter brand — universal calibration, not brand-specific
• 300ml bottle — enough for many calibration sessions
• Stable formulation — pH doesn't drift if stored sealed and away from air exposure
• Recommended every 2-4 weeks — standard calibration practice for accurate readings

Who it's not for:

Don't reuse solution after the probe has been dipped — contamination ruins calibration. Pour a small amount into a separate container each time, then discard after use. Keep bottle sealed between uses; air exposure degrades accuracy over months. Two-point calibration (using both pH 4 and pH 7) is significantly more accurate than single-point; always use both for best results.

In stock now — ships same working day from our Staffordshire warehouse with free UK delivery over £100. Pick up in-store at our Stone shop (ST15 0SR) if you're local, or click & collect at checkout.