Same Brand Thermometers, Different Readings

[Davey Jones]

I would think so, otherwise the thread would make no sense lol

I've learned to never assume!

I prefer the digital ones with a probe in the tank and a wire to the numerical readout on the outside of the tank. Got mine for $10 at a Petco near me, and even checked it vs. a thermometer in the lab at work & it was right on!

I had one of these in my boy's tank, the three spot gourami thought it was fun to attack or play with the probe, flicking it with his tail or biting at it. Had to remove it as the clicking on the glass keep one of my boys awake

 

[The-Wolf]

you may find this interesting
http/www.fishforums.net/index.php?showtopic=111080

 

[rjsmith]

I'm a Science teacher and most of the alcohol thermometers we have read differently. Probably a range of 5 degrees C in a tray full of them. It's kind of expected when they cost £1-2 each. So you will get the same with the any cheap thermometer.
Our Mercury ones are more accurate (and more expensive) but obviously cannot be used in a fish tank.

I would imagine a cheap glass aquarium thermometer to have an uncertainty of at least 1 degree Celcius, maybe slightly more. I checked the error of mine with a digital probe therometer here at school and adjusted accordingly.

 

[bogusmove]

I also have a very reliable........................thermostat in my house set to 26. lol

Surely the water in the tank will be the same temp as the air around it

I don't think that's true actually, although, it perhaps depends on circumstances to be fair.

Presumably you have a heater in your tank? If you had a decent thermometer I'd suggest you could switch it off the heater and monitor the temp carefully, but with a strip, you can't monitor it carefully really I think.

It's been rather a long time since I did all this stuff, but, I think the tank would only necessarily have the same temperature of the air around it if there was no evaporation (which there will be), poor insulation (not sure of the glass qualifies, it's certainly not good insulation) and the specific heat capacity of water was the said as air (but it isn't, it's about 4 times greater).

Thus this means (I think) your tank, without a heater, would cool relative to the room temperature as it evaporates, and the heat transfere from air to water to make up for this would be very slow because a given volume of air has much less heat energy than a given volume of water of the same temperature, thus to raise a cupic cm of water by 1 degree, a cubic cm of air would have to cool by 4 degrees.

Anyone with better and/or more recent science knowledge is welcome to confirm or dispute me ;-)

 

[SuperColey1]

Well according to the thread in the post 2 up. air is an insulator and glass is a conductor and therefore the glass will take the the heat of the water, therefore the LCD will take blah. that thread show the stickystrip is perfectly close enough to accurate.

Also the heater in my tank is set to guess what temp? I might experiment in turning it off and see if the thermostat in the house keeps the water temp correct, come to think of it I rarely see the heater light on so maybe it never has to turn itself on? Maybe its broken and I have nevere noticed. Come to think of it again it does come on when I am changing water.

Therefore changing water, heater comes on because water is not 26C, Once water is 26C doesn't come on until nexst water change. I won't take this as point proven because I think it would be a worthwhile experiment not just in seeing if my house thermostat does the heater job for me, but also in the thinking that what happens in the summer, do I need to buy a cooler to bring the temp back down to 26C.

Oops, maybe costing myself more money here again.