Thermometer placement and temperature swing

[BAINBRIDGE]

Hi fishkeepers

I got a new fangled digital thermometer for Christmas which measures to a tenth of a degree C.

My optimal tank temp is 24.5c. My old mercury thermometer was pretty much spot on because I'm mostly getting a digital reading of 24.5c, however this extra level of accuracy has made it apparent that I get a daily swing between 24.3c and 24.7c, depending on the time of day. I just wondered if anyone else gets a temperature swing too? The tank is out of direct sunlight and not near a heater.

Also, while I'm at it, whereabouts in the tank do people place their thermometers? I put mine in the corner farthest from the water heater, halfway up. I figured it would probably be the best place and would be interested to hear from other fishkeepers.

Thanks

[BigBen]

I have one at both ends of the tank as I thought there may have been a difference at one stage. If the circulation of water is good, it shouldn't matter where it is but I tend to avoid heavy flow areas.

Your thermometer may be more sensitive than your heater as well so the thermostat doesn't kick in when you think it should.

[Vale!]

Yes, BB, the keyword to look up is (as I'm sure you already know) : 'hysteresis'. You'd probably have to couple it with 'heaters' for the results to make any sense!