Looking for an accurate water thermometer

[platinum1]

Does anyone know of an accurate method of testing water temperature? We currently are using a couple of Marina brand digital thermometers but were concerned about the readings ( the water in the tanks felt warmer than what our thermometer reading ) so we tested the water against our personal (for human use) digital thermometer. There was a discrepancy of 9 to 12 degrees Fahrenheit. Is there a more accurate aquarium thermometer that someone can suggest? We also would like it to read from @78 to about 90 degrees F. Any suggestions?

[chintz]

Hi
I got this online from J & L in Vancouver. It works pretty good so far.

http://www.jlaquatics.com/product/mc...ermometer.html

[1Chuck9669]

I use the Lifegard Little Time or Temp on my 125g, and the Corolife ESU Reptile for everything else.

[scolley]

I am intrigued with this question. I too have aquarium thermometers. Quite a few actually. But how am I to know which one is correct? What is the "gold standard" for aquarium thermometers?

The question originally posted is not "what do you use?"... it is "what is accurate?"

Does anyone know of a thermometer that is reliably accurate? And if you are willing to make such an assertion, can you please tell us "why" you know it's reliable?

That would be a real answer to the original post, and I too would be most grateful. Thanks.

[seanyuki]

Thinking of getting one of this....Raytek infrared laser thermometer...anyone tried this product.

http://www.instrumart.com/Product.aspx?ProductID=143


Cheers
Francis

[Darrell Ward]

Thinking of getting one of this....Raytek infrared laser thermometer...anyone tried this product.

http://www.instrumart.com/Product.aspx?ProductID=143


Cheers
Francis

I've never used this exact product, but we do use similar infrared laser thermometers at work. If your try 3 or 4 of them, each one will give you a different reading. Based on this, I don't think they are accurate at all.

[scolley]

IMO all digital thermometers deserve a jaundiced eye, because we tend to confuse precision with accuracy. Digitals will give you an exact number, usually to one or more decimal places - very precise for our purposes. But precise does not mean accurate, as your experience Darrell has shown.

Another example of this is confusion of precision with accuracy is all the hoopla around how "great" LaMotte test kits are. I've got several, and they are not what they are cracked up to be. For example my Alkalinity test kit. I've seen people get really excited about their precision - they resolve your KH tests down to 4 ppm, or less than 1/4 of a degree. Next to the typical pet shop "estimate the color" variety of kits, that fools people into thinking these are great. But the reality is, it's not necessarily very accurate. The 5 ml line on the water sample beaker is (I've measured many times) actually closer to 6.5 ml. So while the unadjusted results of any test with that kit are very precise. But they are off by as much as 30%! Not very accurate.

For that reason, I put absolutely no additional value in precise thermometers. It's accuracy that we need.

For my personal "gold standard" thermometer I went into a pet shop that had about 20 Hagen floating thermometers in stock. I reviewed the temperature of them all, assessed the range, and put the significant outliers back on the shelf. Then I averaged the the temps of all the ones left, and took the thermometer that came closest to that. So, I cannot prove that Hagen floaters are accurate. But my assumption is that they are manufactured against a reliable standard, and that they will, in a somewhat random fashion, be produced with some drift away from that reading. By getting the reading that was the average of those that were not clearly messed up, I figure I've gotten a thermometer that's reasonably close to Hagen's gold standard.

[sophie68]

Hi all,

I got a floating digital thermometer that I quite like. I will have to post a link to it. It is very accurate, albeit a bit large and cost me about 10 dollars. I am saying it is accurate because I have compared what it was reading to what my temperature controller was reading in my main tank.

I also have a Hanna hand held thermometer "checker" with a probe. You just put the probe deep enough in the water to be tested and you can thus compare it to what your current thermometer is saying. I like it so far. It was about $25 on the Fosters and Smith website. The best way to know "exactly" the temperature is to have a commercial grade temperature controller and to check the display. You will always know what temperature your water is. Most reliable as reliable can be in my opinion
Just my 2 cents.

Sophie

[Don Trinko]

Same problem here. I bought several cheap digitals. When I got them they said +/_ 1.5 degrees. Then after abought 6 months they started to read lower, one that was 82 for an actual 84 all of a sudden said 76.
At the moment I rely on the floating thermometers from pet solutions for each aquarium. I do have a digital built into my TDS meter.it reads in centigade but appears to be accurate. Don T.

[kaceyo]

If you want a gaurenteed accurate thermometer you have to buy it at a scientific supply house. Period. Otherwise I do what Steve does. Look at the readings on a large number of thermometers and pick the ones that fall in the average range of all of them. IME, digitals are as bad as any of them for accuracy.

Kacey

[RandalB]

Digital Food thermometers used in kitchens have always been the most accurate ones I've used. Usually within .5 degrees.. About as good as you get on a non lab grade.

RandalB

[krazykat]

What's wrong with the glass alcohol thermometers that are widely available at the pet stores? I use two thermometers in all my tanks - one alcohol inside and the stick-on type on the outside. I place these side by side and haven't had any problems with discrepancy. The outside stick on will read a degree lower but I attribute that to its location on the outside surface and the fact that it's not immersed in water, unlike the alcohol thermometer that I have on the inside. I have similar readings in all my tanks - a degree difference between these two types of thermometers for the same tank.

[pete321]

To check an alcohol thermometer for accuracy, just clean it and stick it in your mouth and check what the temp is . Should read about 98.6. If it is within a half degree then it should be OK. Remember that consistent temp is better than a slightly off temp.

[kaceyo]

What's wrong with the glass alcohol thermometers that are widely available at the pet stores? I use two thermometers in all my tanks - one alcohol inside and the stick-on type on the outside. I place these side by side and haven't had any problems with discrepancy. The outside stick on will read a degree lower but I attribute that to its location on the outside surface and the fact that it's not immersed in water, unlike the alcohol thermometer that I have on the inside. I have similar readings in all my tanks - a degree difference between these two types of thermometers for the same tank.

Hi Krazy,
The problem with thermometers from the pet store is that they arent very accurate. One might read as much as 5 degrees different from the next one on the shelf when both are put in the same tank. They are fine for checking the stability of your tanks water but it helps to know what the temp in the tank really is rather than just coming within a few degrees + or -.
How are the kids doing?

Kacey

[subcooler]

I've used this product for awhile in my job(HVAC service tech).
They accurately read surface temperature.
As long as your in a sealed room(no open windows) along tank wall-I'd say they will always give you accurate tank temp.

I've had problems with several Corallife ESU reptile temp. indicators-They may show true temp. while new , but after a few months +/- upto 5 degrees.
I'd suggest a precision thermometer to be the most accurate option out there(around 25$ online).
Hope this helps,
Rob

Thinking of getting one of this....Raytek infrared laser thermometer...anyone tried this product.

http://www.instrumart.com/Product.aspx?ProductID=143


Cheers
Francis