PINPOINT® II Dissolved Oxygen High-Performance Monitor User's Guide

American Marine is proud to introduce PINPOINT® II Dissolved Oxygen Monitor. The only truly affordable and accurate DO monitoring system. Powered by a 9-volt battery (not included). PINPOINT® II will monitor for approximately 150 total hours before battery replacement is visually indicated on the display as "LOBAT." A 9-volt battery should be utilized for field or intermittent use. For continuous monitoring, the PINPOINT® AC Adapter Kit should be installed. The battery cover is located on the back of the meter toward the bottom (diagram #3-7).

NOTE: The Oxygen Monitor unit is NOT waterproof and must be operated on a dry surface. Liquid contact on the printed circuit board will cause corrosion and void warranty.



  1. Slide the bottom switch #3-3 to the CAL position (toward the right).
  2. With the probe NOT CONNECTED turn the zero adjust screw #3-4 until the display reads 00.0
  3. Fill Membrane Cap with Electrolyte Fluid and screw onto probe body (finger tight only). Remove the dark blue silicone rubber cap at the end of the Membrane Cap.
  4. Connect the probe to the meter by carefully lining up the pins on the plug to the input on the meter. Be sure to fully insert the connector.
  5. Wait several minutes for the probe to polarize and stabilize on the meter.
  6. Turn the O2 calibration screw #3-5 so that the display will read 20.9 This is the percentage of Oxygen in our atmosphere and is widely considered to be a highly accurate calibration procedure.
  7. Slide the bottom switch #3-3 to the DO position (toward the left). The monitor is now ready for use.

Replacement of the membrane cap and liquid electrolyte
The PINPOINT® II Oxygen Monitor utilizes a very high performance polarographic electrode. This Membrane Cap at the end of the probe should be changed frequently to ensure optimum performance. Additional Membrane Caps are available. Please refer to the probe diagram below:

  1. Unscrew the Membrane Cap as from the probe body. This is 1-3/8" from the end of the probe.
  2. Fill a new Membrane Cap with electrolyte fluid. Screw the Membrane Cap onto the probe body (finger tight). A small amount of electrolyte fluid may leak out.
  3. A dark blue protective silicone rubber cap is installed over the tip of the Membrane Cap. This will protect the clear Teflon Membrane surface during storage. This dark blue cap must be removed for both calibration and sample measurement. Reinstall the dark blue cap during storage.

Important Points to Remember

  • PINPOINT® II Oxygen Monitor utilizes a high performance polarographic probe. This probe is epoxy sealed and can be totally submerged if desired.
  • PINPOINT® II Oxygen Meter is NOT waterproof and must be operated on a dry surface. Liquid contact with the printed circuit board will cause corrosion and void warranty.
  • Always wait a minute or two for the automatic temperature compensation to take place before recording any readings.
  • Probe should be inserted about 1 inch into the liquid to be measured. Probe may be totally submerged if desired.
  • While taking a reading you should "swirl" the probe or confirm that there is adequate flow in the sample fluid to insure an accurate reading.
  • The clear Teflon Membrane tip should be moistened with fresh water when taking readings in air and during the regular calibration procedure.
  • It is important that the probe be given a few minutes to polarize during the calibration procedure. This helps to stabilize the readings.
  • The PINPOINT® II polarographic oxygen probe contains an internal temperature thermistor and is automatically temperature compensated for the range of 32°F to 122°F (0° to 50°C). Therefore the displayed value is already compensated and correct.
  • The silver metal sleeve located on the probe tip under the membrane cap should be gently cleaned with steel wool every few months to prevent glazing
PINPOINT® II Oxygen Monitor by American Marine Inc. is warranted to be free of defects in material and workmanship for a period of 2 years from date of sale. Positive proof of purchase is required for warranty claim.

Removal or alteration of the serial number will void warranty.

American Marine Inc. will not be liable for any costs of removal, installation, transportation charges, or any other charges, which may result in connection with a warranty claim.

American Marine Inc. will not be liable for any damage or wear to products or livestock caused by abnormal operating conditions, water damage, abuse, misuse, unauthorized alternation or repair or if the product was not installed in accordance with the printed operating instructions.

Any defective product to must be sent freight prepaid with appropriate documentation supporting the warranty claim. Replacement or repair will be at the discretion of American Marine Inc. Typical turnaround time within 48 hours. Overnight delivery available.