Aqua Medic pH 4 Test Fluid 60ml
Pack size
60 mL
Water type
Freshwater + Marine
Aqua Medic pH 4 Test Fluid 60ml
A pH probe is only as accurate as its last calibration. This Aqua Medic pH 4 Test Fluid is a 60 mL bottle of pH 4.00 buffer solution, used to check and calibrate aquarium pH probes, handheld meters and controllers. Electrode accuracy drifts over time, so re-calibrating against a known buffer at regular intervals is what keeps a pH reading trustworthy rather than just plausible.
Key features
- pH 4.00 buffer solution – a known reference point for calibrating any pH probe or meter.
- 60 mL bottle – enough for repeated calibrations before it runs out.
- Pairs with pH 7 fluid for a two-point calibration – more accurate than calibrating against a single point, particularly if your tank's pH sits well away from 7.
Specifications
| Buffer value | pH 4.00 |
|---|---|
| Volume | 60 mL |
| Use | Calibration reference only – not for dosing into aquarium water |
Suitable for, and not suitable for
- Suitable for: calibrating any pH probe, handheld meter or controller, freshwater or marine.
- Not suitable for: adding to aquarium water – this is a calibration reference fluid, not a pH treatment.
Setup and use
Rinse the probe tip in clean water, then immerse it in the pH 4 fluid and give the reading time to settle before calibrating your meter or controller to 4.00, following that device's own calibration procedure. For a two-point calibration, repeat with a pH 7 fluid and calibrate the second point to 7.00. Rinse the probe again before returning it to the tank.
Care and maintenance
Keep the bottle capped when not in use and away from direct sunlight and heat, and don't return used fluid to the bottle – decanting a small amount into a clean cup for each calibration keeps the rest of the bottle accurate for next time. Buffer solutions drift with age and contamination, so replace the bottle periodically rather than relying on one that's been open a long time.
Goes well with
- Aqua Medic pH 7 Test Fluid 60ml – the second point for a two-point calibration.
- Aqua Medic KCL Solution for pH & mV Probes 60ml – storage solution to keep a probe tip hydrated between uses.
- Aqua Medic pH Probe L127mm - Plastic Standard – a replacement probe to calibrate against this fluid.
Warranty and delivery
Covered by Aqua Medic's manufacturer warranty against defects, in addition to your rights under Australian Consumer Law. Standard freight applies.
Common questions
Do I need both pH 4 and pH 7 fluid?
For the most accurate calibration, yes – a two-point calibration against both buffers is more reliable than a single point, especially if your tank's pH runs well away from neutral.
How often should I calibrate my pH probe?
Aqua Medic doesn't publish a fixed interval, but as a general rule, probes drift over weeks to months rather than days – if your controller's reading doesn't match a manual test kit result, that's a sign it's time to calibrate.
Can I reuse the fluid I've already dipped the probe in?
No – decant a small amount for each calibration and discard it afterwards rather than dipping the probe back into the main bottle, or you risk contaminating the rest of the fluid.
