# The most accurate thermometer?



## olliesshop (Nov 21, 2010)

I've been doing a lot of searching on this site and the web trying to come up with the most accurate and dependable thermometer. I currently have this one ... http://techinstrumentation.com/products ... ation.html ... which seems to be very accurate, but my second one just failed, so I'm looking for a better one.

The two that seem most mentioned are this one ... http://www.petdiscounters.com/Marina-Aq ... 14869.html or the Coralife one ... http://www.fosterandsmithaquatics.com/p ... atid=12089.

I'm very frustrated since I have 5 thermometers measuring the same tank and they all come up with different readings:
- The A150QCERT (before it failed was reading 79.2)
- The bulb thermometer is reading 73
- The heaters are set at 79
- The stick on one is reading about 77
- The infrared thermometer reads about 81

This is such a huge difference !!! Has anyone had any recent experience with theirs that would say theirs is is dead-on?

Any help would be greatly appreciated !!!


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## PfunMo (Jul 30, 2009)

I'm afraid you may be searching for the holy grail! An accurate thermometer that is easy to read and lasts a long time. Perhaps even wanting it to be affordable?? I find there are none that fit what I might want. I use the little dollar variety that stick on the side. They are as accurate as the digital and last a long time at a much lower cost. Most hobby grade electronics are not built with the needed components to factor in the loss of battery voltage as the battery ages so they gradually drift off accurate. It sounds like you may also have thermometers in different parts of the tank where the temperature may in fact be different.

I also find that the temperature is not that critical as long as it stays reasonably steady within a small range. I have no fish that are bothered by 2-3 degrees one way or another.


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## Dj823cichild (Mar 30, 2009)

I have the 2 dollar hang on the side thermo and a digital one they are both identical just about give or take .50 :thumb:


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## prov356 (Sep 20, 2006)

> Has anyone had any recent experience with theirs that would say theirs is is dead-on?


You'd need something beyond hobbyist grade and very expensive. And it'd probably need to be calibrated occasionally. Just not worth it. Get used to going by feel. Few fish need anything more than a good range. I can tell instantly when I touch the water if I'm there and rarely get wrapped up in reading thermometers. And heater settings are even more unreliable. Some will say you can't trust going by feel, and although I'd agree that it can be iffy, I can trust it more than cheap thermometers. I check it every day at feeding time.


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## sjnovakovich (Sep 13, 2010)

Get an instand read thermometer from a restaurant supply company.

http://www.amazon.com/Taylor-Classic-In ... B00004XSC4


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## jrf (Nov 10, 2009)

I jumped through hoops to get some science grade, calibrated and certified digital thermometers (Control Company brand). As prov points out, itÃ¢â‚¬â„¢s not really worth it. They were expensive and the distributor was a hassle to deal with. Since it was a small order and IÃ¢â‚¬â„¢m not a commercial lab, they didnÃ¢â‚¬â„¢t really care about my order. It ended up taking a few weeks, some emails and a phone call to get them shipped. And as mentioned, theyÃ¢â‚¬â„¢re supposed to be recalibrated and re-certified after a certain period of time - not that IÃ¢â‚¬â„¢ll actually do that.

When I got them, I tested them against each other and against my other digitals. Nothing scientific, I just put them all in the same 5 gallon bucket of water. All of the new certified thermometers agreed on the temp within a few 10ths of a degree. My Ã¢â‚¬Å"hobbyÃ¢â‚¬Â


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## olliesshop (Nov 21, 2010)

Thank you all for you words of wisdom. It sounds like I really am looking for the Holy Grail !!! I like the idea of the instant read thermometer from a restaurant supply company. I could drill a hole in my top and let it dangle in the tank or to find one of the stainless steel hang-on thermometers (my LFS doesn't have them for some reason). I'll do some more research.

Like I've said before this is such a great site !!! Thanks again.  :fish:


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## prov356 (Sep 20, 2006)

I've had some luck with another Lifegard. I've been using five of them for about a year now and only one failed, but it may just need a new battery. As far as accuracy, no lab grade equipment to measure by, but they're not all over the board. I have four sump systems in one room and all read about the same at any given time, as they should. There are no heaters in the systems. My storage tank also uses one and it's been consistent also.

HTH


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## krfhsf (Dec 25, 2008)

I just put the back of my hand on the glass of each tank every morning when I feed. If the water is to hot or cold I check it with a known accurate thermometer.


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## olliesshop (Nov 21, 2010)

BTW ... a week or so ago I bought a ~$2 stainless steel thermometer that seems to be the most accurate. It always reads 79 degrees, which is what my Calibrated/Certified one read before it went bad. Goes to show that more expensive is not always better. Also, the electronic thermometer store found the problem in a batch of thermometers and they're sending me a 3rd one now (that they've tested for 10 days) ... hopefully that one will work and I'll use the others as backups.

All the best !!! :fish:


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## Chubbs the Jellybean (Jun 16, 2009)

The glass thermometers have always been pretty accurate for me :thumb:


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## Will1983 (Dec 6, 2009)

i dont think it matters to much on the actual number,

its more important to just keep it constant, as long as it is somewhere around mid range for your fish and steady everything will be fine.


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## adam79 (Jun 27, 2007)

I just use a meat probe thermometer.


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## Teggy (Nov 5, 2010)

I swear by my little laser thermometer. It varies by .5 sometimes so I just check 3 times when I use it to make sure. I have a standard glass thermometer suctioned inside the tank, and it does read accurately, but I still prefer checking with my little pew pew thermo.


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## krfhsf (Dec 25, 2008)

Dad got me this for Christmas. Most accurate easy to read thermometer I have used on my tanks. you do not even have to take the plastic probe housing off. It has holes in it that let the water in. It's also backlit for us blind guy's.

http://www.taylorusa.com/kitchen/thermo ... meter.html


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## szwim (Jan 17, 2011)

I just measure the temperature with a common thermometer. Don't need for specific.


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## Ron R. (Oct 21, 2003)

I use the Lifegard Big Temp digital thermometer and it has been very reliable. I also use a commercial grade Johnson single stage to control 2 500w titanium heaters in my 180g wc moba tank. The Johnson uses a probe as well and the 2 units are pretty darn close.


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## olliesshop (Nov 21, 2010)

UPDATE ... I've been dealing with http://techinstrumentation.com support over the last month or so and it looks like we've solved the problem I was having with the readings going really high. BTW, support has been tremendous. It appears water was getting into the probe, so they completely coated the sensor and about 1/4" of the wire leading into the probe with a PVC sealant/coating and it seems to have fixed the problem. I love the thermometer, since it's calibrated and certified to read the right temperature, although it's $60, which is definitely on the high side for a thermometer. But it also has an alarm if the water temperature goes to high or low. Here's a link again for anyone who's interested ... http://techinstrumentation.com/products ... ation.html


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## tankhead (Aug 8, 2008)

I compared the cheap thermal - stick on thermometers vs a very nice professional model and found the cheap ones to be quite accurate. At least as accurate as an aquarium needs to be. Since they are so cheap, I put one on each end of my 125 and 220 gallon tanks.


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## mrbprint (Nov 15, 2010)

I have always used a glass thermometer I get in a photographic supply place. They are cheap and need to be accurate because the chemicals used in developing film are VERY temp sensitive. I just siliconed them to the cheap ballasted glass aquarium thermometers and let them drop to the bottom and go where they want. Like most have said it is very hard to get 2 to read the same, unless they can be calibrated.


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