# thermometers digital vs stick on



## coryp (May 28, 2008)

hey having a problem my digital thermometer says 77.6 (spare says 78.2) but my stick ons say 86+ whats the deal what one is right?


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## ameekplec. (May 1, 2008)

cheap digital thermometers are notorius for reading incorrectly - get a good liquid (alcohol or mercury) to check it. I use floating thermometers (like $3 each) and they're correct - referenced against 2 high end digital temperature probes (GHL Profilux and Ranco).


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## xr8dride (Feb 24, 2009)

My digi thermometer has a probe but the downfall is it's battery operated...chances are if it's battery operated, as the battery drains and is near dead the readings may be off.


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## Zebrapl3co (Mar 29, 2006)

I tried a couple of digital themometer, they are pretty good if they are accurate.
But in the end, I bought hand held digital lazer thermometer, and then I just zap where ever I want to detect. You'd be amaze that in a little 20G the temperature varried according to depth and how close you are to the heater.
The temperature of the glass does not give you the real temperature of the water inside the tank. It's just an approximate.

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## redclove (Feb 26, 2008)

I'm with Ameek, the oldskool liquid glass thermometers are more trustworthy. 

Why play with fire.


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## xr8dride (Feb 24, 2009)

Do you just keep the floating thermometer suspended in water all the time, or use just when you want to check it? I know how fish like to play with things they see floating around, is that not a risk of it being broken if slammed against the glass wall?


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## redclove (Feb 26, 2008)

mine all have suction cups, I hide it behind the filter/amazon sword, so its not visible when viewing the tank normally, but at a certain angle at the side of the tank I can check it


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## xr8dride (Feb 24, 2009)

Ok now that makes sense to me. I thought you meant a thermometer that just floats around the tank, I believe they were referred to as "The floating glass ones". Thanks for clearing that up.


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## redclove (Feb 26, 2008)

xr8dride said:


> Ok now that makes sense to me. I thought you meant a thermometer that just floats around the tank, I believe they were referred to as "The floating glass ones". Thanks for clearing that up.


both statements true, these are the floating ones, but you can also suction them. occasionally it does come loose and it bobs around.

like these:


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## xr8dride (Feb 24, 2009)

Ahh ok, really Old School...but extremely reliable?


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## redclove (Feb 26, 2008)

tried and true. I def recommend having one alongside a digital thermometer at least until you know you can trust it. But is it not possible that digital ones can go awry over time? I would be weary myself..


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## xr8dride (Feb 24, 2009)

My digital will be replaced by glass now. I've been having a hell of a time getting a duplicate digi for my 2nd 90 at Big Al's anyways...good thing. $3 compared to $15 is a good thing, lol


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## overleaf (Feb 1, 2009)

I use the floaters with a suction cup as well. 

Their readings thus far have been pretty reliable. I found the stick on glass thermometers to be woefully inaccurate due to room temperature interference. Basically my stick on always read 6-8 degrees f more than the floaters.


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## ameekplec. (May 1, 2008)

I've never trusted those stickies, and cheap digital thermometers are just that.

In all the time I've spent aquarium keeping, I've always used an alcohol (red) glass thermometer. 

A few years ago I came upon some lab-grade mercury thermometers (still have em), and checked all my thermometers against them and they were bang on. And in the last few weeks, I've acquired some high end digital temperature sensors, and so far my cheapie glass floater is dead on with the $200 digital temperature controller.


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## jrs (Mar 18, 2006)

Zebrapl3co said:


> I tried a couple of digital themometer, they are pretty good if they are accurate.
> But in the end, I bought hand held digital lazer thermometer, and then I just zap where ever I want to detect. You'd be amaze that in a little 20G the temperature varried according to depth and how close you are to the heater.
> The temperature of the glass does not give you the real temperature of the water inside the tank. It's just an approximate.


What brand did you go with? How durable is it? How accurate is the unit (ie) +/- ??? Do you have a link for it?


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## Zebrapl3co (Mar 29, 2006)

I was looking for the link, but can't find it yesterday. I'll check again ...

Edit:
OK, here it is: http://reviews.canadiantire.ca/9045/0574554P/reviews.htm

Don't buy it at regular price though. It's $99, but about twice a year, it's on sale at %40 - %60 off. I think I got mine for $39.99.

It's pretty durable, I drop it once and it still works. As for accuracy, it's better than the floater, stickys and ditital thermometer. It's supposed to be use by mechanics to check the temperature of a running engine. But I think it's too dinky (inferrior) to be used for serious stuff like that.

One main advantage it has over the other digital thermometer is that there is no contact required. With the digital, you have to constantly clean the digital sensor, otherwise, they become inaccurate because of the stuff building up on the surface.

Just becareful of shoting the fish in the eyes as the laser pointer will surely blind them. (fish have no eye lids )

One thing I notice every time I walk into the thermometer section of a fish store though. You look at a stack of thermometer and they all have different readings. And I just end up walking away because I don't know which one is really telling the truth.

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## xr8dride (Feb 24, 2009)

Here's what people who bought this item at Canadian tire have to say about it!!

#1 - This guy wouldn't know if it were correct or not, he was just fascinated by it..
"I got this on sale for about $25.
cool toy for that price, it was a want, not a needed thing. I ran all over the house the day I got it taking the temperature of everything.
now I just use it to see if my coffee is cool enough to drink. 60oC.
it seems very accurate, just read the instructions, it's not difficult to use.
one day I may even need to use this thing for a real purpose." 

#2 - Seems a little more knowledgable, but not very approving. I found this one a little humorous.
"The price is inexpensive compared to quality models available for >$100, but you don't get much with this unit. Can't switch off laser or irritating beep sound (I KNOW when I am pulling the trigger!). Surprisingly inaccurate, as it reads indoor temperature of only 14 C when it should read 20-21 C. Body temperature reads anywhere between 28-42 C (open your mouth, take aim at back of your throat), when is should read 37 C, this after unit has been sitting indoors at a stable temperature for hours. I compared this unit's temperature readings to those from a higher quality unit that looks very similar and gave results within +/- 1 C. You get what you pay for, and this cheap version under-performs badly. May work better at higher temperatures. Watch for it at my next yard sale."


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