Most Thermometers will show green blue and brown. in most thermometers when the green is showing in the window of the temperature you have the heater set for this would mean the temperatures match. Brown would be the next lowest temp. and blue would mean the temp is climbing to the next degree. but than again different thermometers could have different colors. Read the package and it will tell you what color is what. However any thermometer could vary between + or - one half to one degree of what the heater is set for. with most fish one degree is no big deal. If you have the heater set, for say 78 degrees and the thermometer reads 92 degrees you may have a problem. first get a new thermometer, and if the temp is still reading higher than the set temp on the heater, You need to get a new heater.
answered 4 months ago
Willow Street, PA
0out of 1found this answer helpful.