# Thermometers



## Phatz

Thermometers IMO one of the most essential pieces of equipment needed for a fish tank, but all the ones I have used are all inaccurate and I think its one piece of equipment that needs to be built better and more accurate in reading the TRUE temp not a different temp in each spot of the tank I check. I get rather frustrated as I never know the true temp of my tank. I have the heater set to 76 degrees room temp is about 77-78 degrees but everytime I use a digi thermometer it tells me my temp is 81 degrees and when I use my hang on thermometer I get 78-80 degrees. Yet when I stick my hand in the water sometimes the water feels way warmer like 86 degrees (and that's too hot for my pepper cories)
And others it feels like 74 or lower... Right now im monitoring temp by my hand if its too warm I blow a fan on the tank if its too cold I turn heat up what I want to know are there any real good and VERY ACCURATE thermometers out there right now that anyone could recommend?


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## rjordan390

It may be time to replace the battery in your digital. My digital was not giving correct readings. After replacing the battery, I remembered I had a mercury filled thermometer and used that to test the water temperature and compare it to the digital and digital reading was the same.


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## Agent13

infrared temp gun! I have one for my dragon because her temps need extreme accuracy and for fun I started pointing it at my aquariums water at the surface by the thermometers that were in there. Not very shocked that they are off. Not far..as little as 1 degree to as much as 6(on one). So I would look for one of those if I were you. It's pretty nice to have on hand.


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## Tracy Bird

Agent13 said:


> infrared temp gun!


Never heard of these before, sounded very interesting - pulled up a search on ebay and they look reasonably priced (China Brands)... So you just point them at the water and they produce a reading?.. And they are accurate?

I agree with the original poster, I have a need to do a much better job watching and recording my temps. 

Post up peeps and let us know what's working for you in terms of temperature monitoring...


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## Agent13

Tracy Bird said:


> Never heard of these before, sounded very interesting - pulled up a search on ebay and they look reasonably priced (China Brands)... So you just point them at the water and they produce a reading?.. And they are accurate?
> 
> I agree with the original poster, I have a need to do a much better job watching and recording my temps.
> 
> Post up peeps and let us know what's working for you in terms of temperature monitoring...


Yes Tracy. Those ..even the off brands are very accurate. Only danger with them is you will find yourelf taking the temp of your hands, your floor.. the food you cooked, your windowsill .. But hey..at least they are accurate :lol:

And you can see the difference from one spot of the tank to another very quickly. Just point about 4 inches above the water and click.. that simple.


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## Tracy Bird

I'm definetly going to get one....

You only missed one use agent: How bout accuracy in reading how pissed a spouse gets by their temperature!? .... 

They want to argue and then you whip this out and point it at em'... then you give them their temperature so they'll cool down - anger control device :-D


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## Agent13

hahaha.. I took everyones temp in my house the day it arrived. OMG yes. Put it on you wrist and keep it handy for ANYTHING. I swear I don't even want to tell you al the things I pointed mine at. bwahahaha


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## rjordan390

Check the accuracy of these low cost infared guns. One of them on E-Bay had an accuracy of + or - 1.8 degrees F. Not any better then an otc thermometer.


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## jaysee

I don't monitor temperature at all (I have one thermometer). My tanks are unheated. I know what the ambient air temp is, so I have a good idea of what the tanks are at.

There is this obsession with keeping fish at the top of their preferred temp range, as if that's somehow what's best. Believe it or not, many of the "tropical" fish in the trade don't need 80 degree water.

Temperature fluctuations are normal in nature - only in our aquariums do the fish get a constant temp.....


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## Agent13

jaysee said:


> I don't monitor temperature at all (I have one thermometer). My tanks are unheated. I know what the ambient air temp is, so I have a good idea of what the tanks are at.
> 
> There is this obsession with keeping fish at the top of their preferred temp range, as if that's somehow what's best. Believe it or not, many of the "tropical" fish in the trade don't need 80 degree water.
> 
> Temperature fluctuations are normal in nature - only in our aquariums do the fish get a constant temp.....


Oh hush.. infrared temp guns are fun! Let them get one..because when they get it things get crazy and they'll know temps of things nobody ever needs to get temps of. Plus I can check if my kids have a fever in 1second flat. 
I agree that temps fluctuate a but but having these things can come in handy as long as they do not obsess on "perfect" temps constantly. Actually funny though.. I got mine to make sure there was a good gradient of temp in the dragons home..plus a proper even fluctuation that would be more like nature. Plus how many people can say that this their dogs left ear tends to be be 94.5f ?:lol:

As for accuracy rjordan390.. The ones from ebay tend to notoriously be off. Amazon is better and in stores as well. I check mine against my digital temp probe in the dragons enclosure and the one at the vet. it's right and it's the zoomed one.


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## jaysee

Tracy asked what others do so I shared  I'm not saying not to get one. I'm waiting for the infrared app on my phone...


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## Sanguinefox

jaysee said:


> I don't monitor temperature at all (I have one thermometer). My tanks are unheated. I know what the ambient air temp is, so I have a good idea of what the tanks are at.
> 
> There is this obsession with keeping fish at the top of their preferred temp range, as if that's somehow what's best. Believe it or not, many of the "tropical" fish in the trade don't need 80 degree water.
> 
> Temperature fluctuations are normal in nature - only in our aquariums do the fish get a constant temp.....


It's not true that in our Aquariums they maintain a constant temp even with heaters. There are always minor fluctuations, especially as the house temp fluxes (yes our own homes don't always keep a constant temp).

Of my 5 tanks, it's no surprise that I see temp fluxes. All of them are heated. But it's always a slow few degrees that seems to be related to the temp of the house and how long/frequent the AC is running(or not). While I agree that not all fish need that 80 degrees, there are fish out there that are quite sensitive to not being in the proper water temp. I live in a home where it is usually cold and the windows are drafty til we get that fixed. My tanks loose a lot of heat to this along with the workings of the AC. So for someone like me it's not feasible to do no heaters.

In the winter though it is worse.

OP, you ought to learn to pay attention the behavior of your fish. They will let you know when the water is too hot or too cold. So will the plants if you keep them. I rely more on my animals to tell me what is going on over test kits, and temp readers.


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## jaysee

Sanguinefox said:


> It's not true that in our Aquariums they maintain a constant temp even with heaters. There are always minor fluctuations, especially as the house temp fluxes (yes our own homes don't always keep a constant temp).
> 
> Of my 5 tanks, it's no surprise that I see temp fluxes. All of them are heated. But it's always a slow few degrees that seems to be related to the temp of the house and how long/frequent the AC is running(or not). While I agree that not all fish need that 80 degrees, there are fish out there that are quite sensitive to not being in the proper water temp.


It's all relative. As you yourself said of your own tanks, its a slow change of a few degrees. Compared to the changes that occur in nature, that's pretty constant. Like I said, it's relative to that which you are comparing.


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## pop

Hello:
Jaysee opinion is one that I will go with. You folks that are always fiddling with you aquariums are just making more for you to worry about. Fish keeping is easy if you don’t go out of your way to complicate matters. You can complicate, by improving your aquarium right into a horrible experience. This has happen to me and I learned the less I interfere with the ecology of the aquarium the better off I am as are the critters.

Purple possum rides at midnight!


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## Agent13

pop said:


> Purple possum rides at midnight!


So is this ^ an offer or just a statement? just curious...


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## pop

Hello Agent13;
It’s a pun I always laugh at the thought of a purple possum who rides at midnight. But if you want it could be either an offer or a statement.

pop


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## Tracy Bird

The original posters question was " are there any very good and very accurate thermometers that others could recommend?

Anyone else?
_Posted via Mobile Device_


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## pop

Hello Tracy Bird;
You are right we are talking about excessive accurate thermal measuring devices which do not provide the desired results. There are several problems with these measuring devices. One of the problems is these devices promote the concept that the reading is representative sample of all water molecules in the water column, which is impossible thus forming a false sense of safety and security in water temp. for the fish keeper.

A simple explanation should do and that is the notion of liquid thermal dynamics that states all liquids are heated not by radiant heat but convection energy that operate on the principles of gravity to form thermal convection currents. It works just like a pot of boiling water, when thermal energy is transferred by convection to a water molecule this molecule raises displacing cooler molecules which gravity pulls down to the source of thermal energy creating thermal currents. Thermal currents mean water molecules are in constant motion gaining and then losing thermal energy in the trip around and threw the water column making it impossible to measure a representative sample.

These excessive accurate thermal measuring devices are right up there with 3-D printing in an effort to market these to fish keepers, who in my opinion have no use for them.

Note: disclaimer just because I have an opinion is not proof that I know what I am talking about.

Purple possum rides at sun up!


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## ChuckinMA

I totally share your frustration. My new Marina heater was set to 78, Marina floating thermometer #1 read 84 degrees and Marina floating thermometer #2 read 81 degrees. Ridiculous fluctuations for devices designed to measure temperature. At the advice of my LFS, I took the floating thermometers out of the tank and measured them against the two house thermostats. After recording all the readings, I learned the two house thermostats are reading the same, and one of the Marina floaters was consistently within 0 - 1 degrees of the house thermostats. Turns out the heaters were reading low so I now disregard the numerical setting and adjust based on the floating thermometer reading. 

I'm still not fully comfortable I know what the *real* temp is, so the infrared device is very intriguing. But now I chuckle when fish profiles suggest that say fish "A" prefers a water range 2 degrees warmer than fish "B". How many of us really have the level of precision?


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## rjordan390

Chuck,
The OP asked about a cheap accurate thermometer. The thermometers available to the aquarium industry usually say plus or minus degrees when it comes to accuracy according to the specs. Pop shared a lesson in thermal dynamics which tells us that temperatures in an aquarium can be different in other locations. How much depends on water turn over and currents. So its possible for a 1 degree or more difference at the bottom and top of tank. So I place my sensor in the middle knowing there is a low and high range around that middle. But the difference between low and high is most likely 0.5 to 1 degree. In some tanks, with high intensity lights, may have a range further apart.
So one has to check the specs on a spirit, mercury or infrared thermometer to what the degree of accuracy is.
So fishkeepers should try to stay within the recommended temperature range for the fish and plants and not worry about too much about it except if the temperature is approaching the low or high range.


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## jaysee

The vast majority of thermometers are alcohol. Red = alcohol silver = mercury In case anyone didn't know


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