Growth Technology - Buffer 4 Calibration Fluid

Growth Technology Buffer 4 Calibration Fluid - Keep Your pH Meter Honest

Best for: Anyone with a pH meter, pen or controller who wants readings they can actually trust, not a guess based on a probe that hasn't been checked in months.

Growth Technology Buffer 4 is a calibration solution with a fixed, known pH value of 4.00, used to check and recalibrate pH meters, pens and controllers so their readings stay accurate. Every pH probe drifts over time - the sensing electrode gradually loses sensitivity - and a meter that isn't recalibrated regularly will quietly give you readings that are off, which can lead to over- or under-correcting your nutrient solution's pH without realising it.

Growers House sells Growth Technology Buffer 4 in a 300ml bottle and a 1 litre bottle, giving you the choice of a smaller size for occasional home use or a larger bottle if you're calibrating meters regularly, such as running a grow shop counter or a commercial setup with multiple meters in use.

How it compares

It does the same core job as calibration solutions from other meter brands, at a lower cost per use.

• Bluelab sell their own pH 4.0 calibration solution in 250ml and 500ml sizes, NIST-traceable and formulated specifically for Bluelab meters - a reasonable choice if you own Bluelab kit specifically, but not a requirement for calibrating any standard pH meter.
• Growth Technology's Buffer 4 works across pH meters and pens generally, not tied to one brand, which matters if you own more than one meter or a mix of brands.
• At this price point, buying both Buffer 4 and Buffer 7 together costs less than most single-brand-specific calibration kits, without any loss of accuracy for standard two-point calibration.

You don't need to match your calibration fluid to your meter's brand - what matters is using a genuine, unopened buffer solution and not reusing it once it's been exposed to a probe.

Usage guidance

Calibration only takes a couple of minutes, but doing it properly makes a real difference to accuracy.

Two-point calibration
Calibrate with Buffer 7 first to set the meter to neutral, then use Buffer 4 to set the second calibration point. Using both gives a far more reliable result than calibrating to a single buffer alone.

How to use it
Pour a small amount of Buffer 4 into a clean, separate container - never dip the probe straight into the main bottle. Place the probe in the solution and follow your meter's calibration procedure.

Don't reuse it
Once buffer solution has been used to calibrate a probe, discard it rather than pouring it back into the bottle - contamination from the probe will throw off future calibrations.

How often
Recalibrate at least monthly, and more often if you're using your meter daily or if readings start to look inconsistent between checks.

Technical specifications

• Type: pH calibration/buffer solution
• Calibration value: pH 4.00
• Sizes available: 300ml, 1 litre
• Use with: most standard pH meters, pens and controllers
• Storage: keep sealed and out of direct sunlight; discard used solution, don't return it to the bottle

Who this is for

• Any grower using a pH meter, pen or controller who wants to trust their readings
• Growers who've noticed their pH readings drifting or not matching expected results
• Anyone running multiple meters who needs an affordable, brand-neutral calibration fluid
• New growers setting up their first pH meter and needing calibration fluid from day one

Our take

It's a small, unglamorous bottle that does one very specific job - keeping your pH meter honest - and it does it reliably. Skipping calibration is one of the easiest ways to end up chasing pH problems that don't actually exist, because your meter was the thing that was wrong.

Grab a bottle of Buffer 4 and Buffer 7 together and get into the habit of calibrating monthly. Does exactly what it should, day in, day out.