Jaguar Coolant Tank Level Testing & Repair

The first time I performed this test the meter indicated a change before the water level reached the bobber to make it move. I checked the bobber and removed the probe to see what I could find. Not knowing how the probe worked I wanted to try and figure it out first. I took the probe and ran cold water directly over it and noticed a change in continuity. I changed the water temperature to warm and noticed the readings changing on the meter. I cleaned the probe and put it back into the tank and performed several tests no change. That evening I removed the probe and attempted to use light and reflection to see what made the probe work. In fact I scraped the surface of the probe slightly to see if I could get a better look. In the process of doing that I noticed that the probe was a lot cleaner. It then dawned on me that the deposits on the probe had something to do with the readings. It all changed after the whipping and scraping the probe. I made 10 additional tests with cold and hot 5 each and no major change. I did however use hot water at 185 temp and had a slight change 2 times. I plan to remove my probe and see what I find. If this is the case I would recommend a good cleaning of the probe and the channel it goes in. Thank You Brian for your tank...