P50 Pro Replacement Electrode by Aqua Master Tools — pH & Temperature Probe for the P50 Pro and P50 Pro2 Pens
AMT-METER-ELEC-P50PRO
Genuine Aqua Master Tools replacement pH and temperature electrode (AMT1001) for the P50 Pro and P50 Pro2 pens. Unscrew, swap, recalibrate. IP67 once fitted.
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Pairs well with
A pH pen does not die all at once. The glass bulb slowly loses its response, readings start to drift, calibration takes longer to settle, and one day it will not hold a calibration at all. On most pens that means buying a new meter. On the Aqua Master Tools P50 Pro and P50 Pro2 it means unscrewing the sealing ring and fitting this genuine replacement electrode (part AMT1001). It is the same pH and temperature sensor the pen shipped with, it is IP67 waterproof once fitted, and the swap takes a couple of minutes without tools. It fits both generations of the P50 and nothing else in the Aqua Master range.
Specifications
Grower's Tip
- Before you buy, try a clean and recalibrate. A bulb coated in nutrient film reads slow and drifty exactly like a worn one. Ten minutes in electrode cleaner, a rinse, then fresh pH 7 and pH 4 buffers. If it calibrates and holds, you did not need a new electrode.
- Signs it really is worn: calibration fails or will not settle, readings drift while the pen sits in a stable buffer, the response time has blown out to a minute or more, or the glass is visibly cracked or chipped.
- Use fresh buffer solution for the first calibration on a new electrode. Old buffers that have been dipped a dozen times are contaminated and will calibrate the new sensor to a wrong number.
- Never store a pH electrode in distilled or RO water. It pulls the ions out of the glass and shortens its life. Tap water is fine for the pre-use soak; KCl storage solution in the cap is best for day to day.
- Rinse the electrode with water after every reading and put the cap back on. Dried nutrient salts on the glass are the main reason pH electrodes wear out early.
- Do not plunge a cold electrode into hot liquid or the other way round. Sudden temperature swings can crack the glass bulb, and that is not covered by warranty.
- Keep the old electrode's rubber seal if the new one looks different. Aqua Master's instructions have you check the seal is seated before tightening, and a mis-seated seal is how water gets into the pen.
How To Fit It
Want to see it done first? Watch Aqua Master Tools' electrode replacement video on YouTube.
Pairs Well With
The pen this electrode fits. If the body or display has given up rather than the bulb, this is the fix instead.
Flairform pH Buffer 7.0First point of the P50's 2-point calibration. Fresh buffer for a fresh electrode.
Flairform pH Buffer 4.0Second calibration point. You need both to calibrate the P50 properly.
Flairform pH Electrode Storage SolutionA few drops in the cap keeps the glass hydrated between readings. Aqua Master recommends storing the P50 this way.
Flairform Electrode CleanerClean the bulb before you condemn it. Regular cleaning is what makes the next electrode last longer than the last one.
Meters & Pens – pH & EC TestingEvery pH, EC and combo pen we stock, plus the probes and solutions that keep them honest.
Frequently Asked Questions
Does this electrode fit the P50 Pro2 as well as the original P50 Pro?
Yes. Aqua Master Tools makes a single P50 electrode, part AMT1001, and lists it as the replacement for both the P50 Pro and the P50 Pro2. The Pro2 changed the display, batteries and firmware, not the electrode.
Will it fit the P110, P160 or E50 pens?
No. Each Aqua Master pen family has its own electrode and they are not interchangeable. The P160 Pro and Pro2 use the P160 electrode (AMT1019), the P110 uses AMT1014 and the E50 uses the E50 EC electrode. Check the model name printed on your pen before ordering.
How do I know the electrode is worn and not just dirty?
Clean it first. Soak the bulb in electrode cleaner, rinse, then calibrate in fresh pH 7 and pH 4 buffers. If the pen still will not calibrate, drifts while sitting in a stable buffer, or takes more than a minute to settle, the glass has had its day and this electrode is the fix.
Do I need any tools to replace it?
No. The sealing ring at the base of the pen unscrews by hand, the old electrode pulls straight out and the new one pushes in. Aqua Master's own instructions are seven steps and most of them are "check the seal" and "calibrate".
Does the pen need recalibrating after I fit the new electrode?
Yes, every time. The calibration stored in the pen belongs to the old electrode. Soak the new one for 12 hours, fit it, then run the 2-point calibration in pH 7.00 and pH 4.01 before you trust a single reading.
Why does the new electrode have white crust on it?
That is dried salt from the electrode's internal solution and Aqua Master says it is normal. The 12-hour soak in tap water dissolves it and rehydrates the glass. It is not a fault and it is not a sign the part is old.
Is the pen still waterproof with a replacement electrode?
Yes, provided the rubber seal is seated and the sealing ring is done up tight. Aqua Master rates the electrode IP67 when attached to the meter, the same as the pen out of the box.
How long should a P50 electrode last?
It depends on how it is treated, and Aqua Master does not publish a figure. Rinsed after every use, capped with storage solution and kept out of concentrated nutrients and pH adjusters, a pH electrode lasts a long time. Left dry on a bench with nutrient crust on the glass, it will not. The warranty on the electrode itself is six months.
Fix the pen, keep the pen
Genuine Aqua Master Tools P50 electrode, shipped from Tasmania. Free shipping over $499*.
