Our newer versions of our dissolved oxygen probes that are included with the dissolved oxygen sensors (both PASPORT (PS-2108) and ScienceWorkshop (CI-6542) and our water quality sensor (PS-2169)have incorporated the temperature sensing element into the probe tip. This helps make sure that this element is immersed within the water that is being tested.
When you are filling the probe head with the polarographic solution, please make sure that you are grasping the probe tip below the main body of the probe so that the top of the probe can be properly removed.
The top probe is the older style probe with the exposed temperature compensating element. The bottom probe has this element included within the probe tip so it is not visible from the outside.