Bluelab PPM Conductivity Pen

What the Bluelab PPM Pen Reads, and How Close Nutrient charts do not agree on units, which is why this pen lets you pick. It covers ppm 500 from 0 to 5000, ppm 700 from 0 to 7000 and EC from 0.0 to 10.0. Accuracy runs ±50 ppm on the 500 scale, ±70 on the 700 and ±0.1 EC, measured at 25°C. Temperature comes along as well, 0 to 50°C or 32 to 122°F, to within a degree. Automatic temperature compensation does quiet work behind all of it. On an uncompensated meter a cold reservoir reads low and a warm one reads high. That gap is wide enough to move a feeding decision. This one arrives factory calibrated, so the first reading is a reading rather than a setup job. Living With a Conductivity Pen Day to Day The care routine is short. Rinse it under running water after every use so nutrient salts do not build up on the electrodes. Clean the probe properly about every two weeks. That is the whole of it, and skipping it is the usual reason a pen starts reading oddly. Calibration is optional on a conductivity meter, which is not true of a pH one. A bottle of 2.77 EC standard is a check here, not a chore. The body is fully waterproof and it floats, which matters more than it sounds when you are leaning over a full tank. A backlit screen, a hold function, auto off and a low battery warning cover the rest, on one AAA cell. The probe is not replaceable. When the electrodes eventually go, the pen goes with them. Anyone who would rather change a probe than a meter should look at the OnePen. Key Features Selectable units: ppm 500, ppm 700 or EC, so it matches whichever scale your nutrient chart uses. Reads to ±50 ppm: On the 500 scale, or ±70 on the 700 scale and ±0.1 EC at 25 degrees. Automatic temperature compensation: A cold tank reads low on an uncompensated meter. This one corrects for it. Temperature as well: 0 to 50 degrees Celsius, or 32 to 122 Fahrenheit, to within a degree. Factory calibrated: Ready on arrival, and calibration stays optional rather than routine. Waterproof and it floats: Useful the first time it goes into a full reservoir by accident. Two week cleaning cycle: Rinse after each use, clean the probe properly every couple of weeks. Backlit with hold and auto off: Plus a low battery warning, all running from a single AAA cell. Probe is not replaceable: When the electrodes fail the pen is finished. The OnePen takes a new probe. One year warranty: Repair or replacement, from Bluelab. Technical Specifications Specification Value Brand Bluelab Part Number 716482 Product PPM / Conductivity Pen Measures Conductivity and temperature EC Range 0.0 to 10.0 EC, ±0.1 at 25°C ppm 500 Range 0 to 5000 ppm, ±50 ppm 700 Range 0 to 7000 ppm, ±70 Temperature Range 0 to 50°C / 32 to 122°F, ±1°C Units Selectable for conductivity and temperature Temperature Compensation Automatic Display Backlit LCD Functions Hold, auto off, low battery warning, calibration indicator Calibration Factory calibrated. Optional, using 2.77 EC standard Water Resistance Fully waterproof, floats Power 1 x AAA alkaline battery Probe Not user replaceable Cleaning Rinse after each use, clean the probe every two weeks Warranty 1 year repair or replacement