What is the difference between membrane and optical DO probes?

MANTECH recommends the optical probe and ~90% of MANTECH customers use optical probes.

MANTECH supports both membrane and optical DO probes as both are approved by SM 5210B.

Maintenance - The main benefit of optical over membrane is the maintenance aspect.

  • Membrane probes are much more sensitive to storage conditions, operating practices, and the membranes need to be changed quite often.
  • Optical sensor caps last a lot longer and storage is not as critical, though our systems do still store automatically regardless of probe type.
Stability Time
  • Stability timing for each measurement is similar, can take a bit longer for optical vs membrane.
  • Stability of the measurements over an entire run or between multiple runs is better with the optical.
For these reasons, MANTECH recommends the optical probe and ~90% of MANTECH customers use optical probes. Ultimately, it is your preference and MANTECH BOD systems support either probe.