| Identification |
| Model / SKU | PT4 |
| Brand | Myron L® Company |
| Product Type | Ultrapen™ handheld instrument |
| Measures | Free Chlorine Equivalent (FCE™) & Temperature |
| Country of Origin | United States |
| Measurement |
| FCE Free Chlorine Range | 0-10.0 ppm |
| FCE Accuracy | < 5.00 ppm: ±0.3 ppm; ≥ 5.00 ppm: ±0.5 ppm |
| FCE Resolution | 0.01 ppm |
| Temperature Range | 0-71 °C / 32-160 °F |
| Temperature Accuracy | ±0.1 °C |
| Method | Measures ORP cross-referenced with pH to report free available chlorine on the unaltered source water |
| Physical & Power |
| Temperature Compensation | Automatic to 25 °C |
| Battery | One N-type alkaline 1.5 V (installed) |
| Operating / Storage Temperature | 0-55 °C / 32-131 °F |
| Body | Aircraft aluminium, epoxy-encapsulated electronics, waterproof |
| Physical Dimensions | 17.15 cm L × 1.59 cm D / 6.75 in. L × 0.625 in. D |
| Weight | 50.4 g / 1.78 oz |
What is in the box
PT4 pocket tester pen with battery installed, protective cap
Warranty
Two (2) Year Limited Warranty on the instrument. pH and ORP sensors carry a Six (6) Month Limited Warranty. Warranty is limited to repair or replacement at the manufacturer’s discretion and excludes damage from abuse, tampering or environmental extremes.
WHERE THIS IS USED — 2 APPLICATIONS
Myron L publishes an application bulletin for each of these. The summaries below are ours; the linked bulletins are Myron L’s own and open in a new tab.
Environmental Monitoring
Wastewater, stormwater, surface water
Discharge to waterways, to municipal sewers and increasingly stormwater runoff all sit under permit limits, and demonstrating compliance means measuring at many points rather than one. Conductivity, pH, ORP, dissolved oxygen and nitrate together characterise both the health of a receiving water and the quality of an effluent, and handheld instruments make it practical to sample where the water actually is.
Measured here: Conductivity / TDS, pH, ORP, dissolved oxygen, nitrate, temperature
📄 Environmental Monitoring Application Bulletin (PDF)Oxidation Reduction Potential (ORP / Redox)
Disinfection, process control, water treatment
ORP measures the strength of the oxidisers and reducers present rather than their concentration, and it is reported in millivolts with no temperature correction. That distinction matters: a chlorine residual tells you how much is there, while ORP tells you how effectively it is actually oxidising. Positive readings indicate an oxidising solution such as chlorinated water; negative readings indicate a reducing agent such as sodium sulfite.
Measured here: ORP / redox, pH, free chlorine equivalent
📄 Oxidation Reduction Potential (ORP / Redox) Application Bulletin (PDF)Application areas are those in which the Myron L® Company’s own application bulletin names this instrument. Bulletins are reproduced unaltered with Myron L’s copyright notices intact. Suitability for a specific installation should be confirmed with us before purchase.
Specifications taken from the Ultrapen™ PT4 Data Sheet and myronl.com, published by the Myron L® Company. Myron L reserves the right to change design, specifications and prices without notice — please confirm critical figures with us before purchase. Myron L®, Ultrameter®, Ultrapen™, UltrapenX2™, TechPro™, PoolPro™, bluDock™, Guardian2™, FCE™ and 442 Natural Water™ are trademarks of the Myron L Company. VALOX® is a registered trademark of SABIC. Bluetooth® is a registered trademark of Bluetooth SIG, Inc.
