How accurate is temp reading on tds stick.
Out of curiosity i checked temp of water in my tank. 500 ltr left in all day since last night. The reading was 9.2 c the reading outside the tank but inside the back of van was 10.2 c and the reading of temp outside van in nights air was 3 c.
Its a frosty night, so ive now put radiator on, on a timer throughout night. But thought water temp is good. But how good is the reading from these things