Myron L Ultrapen Replacement Sensors — PT2, PT3, PT4, PT5 and PT6
User-replaceable sensors for Myron L Ultrapen and UltrapenX2 pocket testers. When a pen slows down, drifts, or stops holding calibration, the sensor — not the instrument — is almost always the part that has reached end of life. Each sensor installs in the field with the instructions supplied in the box; no return-to-factory service required.
Application
Keep a spare sensor with any pen that lives on a sampling route. pH and ORP sensors are consumable by design (typically 6–12 months of regular use, less in hot or fouling water); DO and nitrate sensors last longer but still age. Pens using the same sensor family across the wired PT and Bluetooth PTBT models share these part numbers.
Which sensor do I need?
- RPT2 — pH, with the porous liquid-junction design used in PT2 / PTBT2
- RPT3 — ORP / redox, 99.9% pure platinum electrode, PT3 / PTBT3
- RPT4 — Free Chlorine Equivalent, PT4 / PTBT4
- RPT5 — dissolved oxygen, PT5 / PTBT5
- RPT6 — nitrate, PT6 / PTBT6
- DOM5K — membrane, fill solution and syringe service kit for the PT5 DO sensor
Documentation
Also order pH/ORP Sensor Storage Solution and the matching calibration standards from Myron L Parts & Accessories.