Problems with digital thermometer?

[djheywood]

I have had one of the dual display digital thermometers on my reef for about 2 years. Do these things lose temperature calibration? My tank has been getting very hot lately, it shows like 91 F but then I bought a cheap floating glass thermometer and it shows 83 F. I know my tank is not 91 F as the water feels cool to the touch. Has anyone else experienced inaccurate readings like these?

Thanks.

 

[Mekinnik]

try submersing it in a glass of icewater (must be ice with water in it). If your thermo. reads 32 deg. +/- 2 deg. then it works fine and is not out of calibration.

 

[Anonymous]

Ya beat me to it...Mekinnik, I was just going to say that.

dj,
Battery operated units have a tendency to do this kind of thing when the batteries are low. My pH monitor was reading in the high 10s before I realized something was wrong with the meter, not my tank!

 

[djheywood]

well, i just tried the ice water trick but the unit caps on the low end at 58 F. I replaced the battery and put in back in the sump and it is still registering 90 F. What would you guys trust, a 2 year old digital, or a 2 day old floating glass thermometer? I guess I will go buy another one and see if the third confirms either of the two. Again the water does not feel warm to the touch. Anyone know at what temp the water stops feeling cool?

 

[Mogo]

You may want to put your floating glass thermometer in the ice water as well to get a comparison.