Bluelab Replacement pH Probe

A replacement BNC-connection pH probe compatible with all Bluelab products that use a BNC connector, including the Combo Meter and Guardian Monitor. The double-junction reference design reduces contamination from nutrient solutions entering the reference junction, extending probe working life compared to single-junction alternatives. Polycarbonate housing provides robust protection for daily use in growing environments.

A 2m cable allows the probe to be used in hard-to-reach reservoir positions without repositioning the meter. The included KCl-filled storage cap keeps the probe hydrated between uses, which is critical to maintaining both response time and measurement accuracy. A dry probe cannot be recovered. Effective in solutions of 0.2 EC and above. pH probes are consumable items and should be replaced when calibration can no longer bring readings within acceptable accuracy. Always keep the probe tip submerged in storage solution when not actively measuring.

A note on pH probe care and warranty: pH probes and pH pens are precision scientific instruments and require consistent care and maintenance to provide accurate readings and remain within warranty. Please read the full instruction booklet included with your instrument before use.

pH probes and pens (without replaceable probes) are electrical sensors and are considered consumable items, in the same way that growing media and nutrients are replaced over time. The live charge in the sensing electrode degrades naturally with use, and hydroponic nutrient solutions accelerate this process significantly compared to other applications. Probes and non-replaceable pens carry a 6-month warranty from the date of purchase. Proof of purchase is required for any warranty claim.

With correct care, a pH probe can last considerably longer than 6 months. Without it, the electrode can fail well within that window. The two most important rules are simple: always rehydrate the probe in storage solution before use, and always store the probe in storage solution when not in use. In-tank monitors are the exception to the storage rule, as the probe remains submerged during operation. Storage solution is available in stores and should be considered an essential part of your pH monitoring setup. If it dries, it dies.