Electronic Thermometer Problems?

[avshockey311]

I have had an electronic thermometer in my tank for the past 4 or 5 month now. I started noticing a big difference in my temp between my FW tank and my SW tank when I had my hands in the tank. So out of curiosity I checked my SW tank against 2 different thermometers, come to find out my electronic thermometer that is supposed to be within 1 degree is almost 12 degrees cooler than the actual temp. It said 78 and the actual temp is 90. Has anyone had this problem. What thermometers do you use? 12 degrees off is A LOT!!!! good ole e-bay.

[tanker]

What brand are you using?? Is there something on the probe?? Coraline, algae, ect can cause false readings.

[tanker]

I have 5 tanks and the all have a electronic thermomiter--have no problems. I move them around between tanks once in a while just to make sure they all working properly.