Water feels cold but temperature reads 80+

[Kody]

So i just got a new thermometer for my fish tank. It reads 82 degrees but when i put my hand in the water it feels a little chilly.

I put my thermometer in water from my drinking water that was cold and it read about 50 degrees


but i put it in my tank which feels cold and the temperature say 80+ degrees why is this?

 

[pisanoal]

80 degrees is cold compared to your body temperature. Depending on ambient air temp, and what you are "acclimated" to at the time you stick your hand in the tank, it might feel cold. Trust the thermometer more then your hand, its what it was designed to do.

 

[ptreef]

or buy another thermometer and compare.

 

[DivingTheWorld]

Always run two thermometers for this reason. They're cheap, no reason not to.

 

[CafeReef]

Also make sure that the thermometer is not "close" to your heater, this can throw off the thermometer. I have a apex probe thermo in my sump in the baffle before the return (2 sections away from my heater) and another in my overflow in my display.

As well as your typical suction/mercury (I know mercury isn't the case anymore just cant think of the term) in the sump compartment immediately after my heater.

 

[Ron Reefman]

Go swimming in a pool that is 80F and tell me it doesn't feel somewhere between cool and cold when you first get in. Sure you get use to it, but at first it feels cold. And if you stay in a long time, it will cool your core body temp and you'll feel very chilly.

 

[sil40sx]

Yup, sounds normal.

If you have doubts, grab another thermometer and compare readings.

 

[Sk8r]

Keep a peel n stick thermo strip on sump or tank, and a digital thermometer in tank. Sometimes they do lie.

 

[thegrun]

A good lab grade thermometer is a must have IMHO. It is common for hobby thermometers and heaters to be off by several degrees.

 

[Xxero]

A good lab grade thermometer is a must have IMHO. It is common for hobby thermometers and heaters to be off by several degrees.

Any recommendations or links to a good lab grade thermometer?

 

[Timfish]

80 degrees is cold compared to your body temperature. Depending on ambient air temp, and what you are "acclimated" to at the time you stick your hand in the tank, it might feel cold. Trust the thermometer more then your hand, its what it was designed to do.

+1

 

[DonR]

Any recommendations or links to a good lab grade thermometer?

This is the one I use:

https://www.amazon.com/gp/product/B019QNBV04/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

"Traceable" means the thermometer has been calibrated using a recognized authority's published procedure (the National Institute of Standards and Technology in the US), and verified with a known fixed temperature standard or by comparison to another thermometer that is traceable. This thermometer ships from a reputable scientific supply vendor, and includes a certificate of calibration. While the NIST does not monitor claims of traceability, purchasing from a reputable vendor provides that assurance.

Digital thermometers like this one need to be sent in to be re-calibrated about once a year if you want to maintain confidence that they are accurate. The certificate that came with my thermometer expires in about a year. Traceable analog thermometers (glass thermometers filled with mercury or alcohol) should maintain their accuracy much longer than electronic thermometers. I have a traceable darkroom thermometer that I got about 40 years ago, but I have misplaced it. No doubt I put it somewhere safe, but recently I spent hours looking for it, and ended up buying this digital thermometer.

I have no affiliation with the NIST or with the vendor of this thermometer, but I have purchased from this vendor several times, and have never been short of fully satisfied with those purchases.

Don

 

[ReefsandGeeks]

If it's hot outside and I just came inside, touching my 80 degree tank feels cold, but at the same time if it's been cool or cold outside and I touch the water with cold hands, it feels very warm. "feel" is relative, so a thermometer or two is really the only way to have confidence in temp.

 

[Butch01]

You can die of hypothermia in 80 degree water... If the veins in your hand are distended, water of the same temperature will feel colder than if the veins are contracted. Your nervous system is a very bad thermometer for things like that.

 

[Fnic99]

I had the same thought the other day. The water felt cold and I thought the heater was broken. Checked with 2 thermometers and water was 78. I guess it just feels cold to us.

 

[fishchef]

Place the probe in a glass of ice water. Should be about 32 F.

 

[rocsec1]

Brs has calibration probes so you can check it is accurate

 

[Xxero]

This is the one I use:

https://www.amazon.com/gp/product/B019QNBV04/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

"Traceable" means the thermometer has been calibrated using a recognized authority's published procedure (the National Institute of Standards and Technology in the US), and verified with a known fixed temperature standard or by comparison to another thermometer that is traceable. This thermometer ships from a reputable scientific supply vendor, and includes a certificate of calibration. While the NIST does not monitor claims of traceability, purchasing from a reputable vendor provides that assurance.

Digital thermometers like this one need to be sent in to be re-calibrated about once a year if you want to maintain confidence that they are accurate. The certificate that came with my thermometer expires in about a year. Traceable analog thermometers (glass thermometers filled with mercury or alcohol) should maintain their accuracy much longer than electronic thermometers. I have a traceable darkroom thermometer that I got about 40 years ago, but I have misplaced it. No doubt I put it somewhere safe, but recently I spent hours looking for it, and ended up buying this digital thermometer.

I have no affiliation with the NIST or with the vendor of this thermometer, but I have purchased from this vendor several times, and have never been short of fully satisfied with those purchases.

Don

Well, I'm sold.....Thank you for the info.! :bigeyes:

 

[Cakebaker13]

Does anyone have any experience using high quality food grade thermometer vs a lab grade thermometer? just curious

 

[MmmmBalf]

The reason the water feels cool is that your hand is not a very good thermometer. The temperature it feels is related to the rate of heat exchange more than the actual temperature of what it's touching. For example, touching something metal inside your house, a knife etc, will feel cold. Actually that metal will be at room temperature. It feels cold because metal is a strong conductor and takes heat from your skin quickly. Likewise the water feels colder than it is because the water (when it's cooler than your body temperature) takes heat from your skin faster than air does - it's a better conductor. 25º (77F) water will feel much colder than the same air temperature.