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Bluelab pH Calibration Solution 4.0
Bluelab pH Calibration Solution 4.0 is a precision reference solution used to calibrate pH pens, meters, and probes, ensuring ongoing measurement accuracy in nutrient solutions and water. Regular calibration is essential for maintaining reliable pH readings, particularly in hydroponic systems where small variations can influence nutrient availability.
This solution provides a stable pH 4.0 reference point and is used as part of a two-point calibration process alongside pH 7.0 calibration solution. By calibrating at two points, the pH device can correctly interpret both neutral and acidic ranges, helping maintain consistent and dependable readings across typical growing conditions.
Bluelab recommends routine calibration to account for probe drift over time. Using fresh calibration solution during each calibration cycle supports consistent results and helps extend the functional reliability of pH measurement equipment. This solution is formulated specifically for compatibility with Bluelab pH products and is intended strictly for calibration purposes, not for storage or adjustment of pH in nutrient solutions.

Accurate reference point
Provides pH 4.0 calibration
Supports routine care
Used in regular calibration
Supports accuracy
Maintains reliable readingsA calibration solution that supports accurate Bluelab pH measurement through regular two-point calibration.
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Bluelab pH Calibration Solution 4.0
Key Highlights
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Key Highlights
- Provides a pH 4.0 reference standard for calibrating Bluelab pH products.
- Supports regular maintenance to help keep pH pens, meters, and probes accurate over time.
- Forms part of Bluelab’s recommended two-point calibration process with pH 7.0 solution.
Directions for Use
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Directions for Use
- Clean and hydrate the pH pen or probe before calibration.
- Calibrate first in fresh pH 7.0 calibration solution.
- Rinse the probe tip in clean tap water and shake off excess water.
- Place the probe tip in fresh Bluelab pH 4.0 Calibration Solution and allow the reading to stabilise before completing calibration.
- Recalibrate before first use, after cleaning and hydration, after changing batteries, or when the calibration reminder has disappeared.
Bluelab recommends calibrating once a month.
Resources
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Resources
Shipping & Returns
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Shipping & Returns
We have a 30-day return policy, which means you have 30 days after receiving your item to request a return.
To be eligible for a return, your item must be in the same condition that you received it, unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase.
To start a return, you can contact us at info@hydrooasis.com.au
If your return is accepted, we’ll send you a return shipping label, as well as instructions on how and where to send your package. Items sent back to us without first requesting a return will not be accepted.
You can always contact us for any return question at info@hydrooasis.com.au.
Size: 18ml