Ideally, you put the thermometer near the top of the beer line in the fermenter and above the water line in the swamp cooler. Also, they are designed to read looking straight at them and a bit shiny. If you are trying to see them at an angle, the reflected light might make it harder to read.
Stick On Fermenter Thermometer Strips
Sticks to plastic fermenters and glass carboy/demijohns as well as Erlenmeyer flasks. Gives an accurate temperature between 10 and 40 degrees Celcius.
Availability: 37 in stock