Sea-bird Scientific no longer directly sells and ships Triton-X. Since January 4th,2021 Triton-X has been banned in the EU due to a key ingredient being a known endocrine disrupter.  TERGITOL is a non-ionic surfactant which can be used as a substitute for Triton-X. It can be purchased at Sigma Aldrich.  The surfactant is supplied in 100% strength and will need to be diluted. If neither surfactant is available, vinegar or a diluted bleach solution can be used as a substitute.
Conductivity sensors — TERGITOL is typically diluted to 0.1% strength (by 1000) for rinsing and for rewetting the conductivity cell just before deployment, and to 1% to 2% strength (by 50 to 100) for cleaning the conductivity cell. Refer to Application Note 2D: Instructions for Care and Cleaning of Conductivity Cells and to the maintenance section in the instrument manual for details.
SBE 43 (membrane-type) Dissolved Oxygen sensors — TERGITOL is typically diluted to 0.1% strength (by 1000) for rinsing, and to 1% (by 100) for cleaning. Prolonged exposure of the sensor membrane to Triton causes the sensor's calibration to drift. Do not place Triton directly on the membrane. See Application Note 64: SBE 43 Dissolved Oxygen Sensor - Background Information, Deployment Recommendations, and Cleaning and Storage for details.
SBE 63 Optical Dissolved Oxygen sensors — TERGITOL is typically diluted to 0.1% strength (by 1000) for rinsing, and to 1% (by 100) for cleaning. Do not place TERGITOL directly on the optical window. See the SBE 63 manual for details.