Different Thermometers, Different Readings

[The-Wolf]

Inspired by a recent post
I decided to put all the different types of thermometers that
I have, in one tank and see if they read the same temp.
They didn't, well not quite.

From top to bottom; left to right (All prices approximated)
Marina; Thermosensor £6.99
Can be set for C or F
27.1C (the lowest in this test)

Marina; Aqua-minder £14.99
Can be set for C or F. multiple functions
28.5C

Hagen; Digital strip £1.20
shows bothe C and F, reads glass temp, not water temp
27/28/29C hard to tell exactly.

Penn Plax; Floating glass thermometer £1.99
shows both C and F, easily broken if knocked accidently.
28C

Fish 'R' Fun; Digital thermometer £9.99
Reads C only
28C

Super Fish; Digital thermometer £6.99
Reads C only
28.6C (highest in this test)

conclusion
all thermometers seem to have a tollerance of +/- 1C.
If you want acuracy and cheapness then the floating glass thermometer gets my vote.
I, however, am impressed with the Marina Aqua-minder, I especially like the min/max
temp alarm facility which could save some lives in the future.

Hope this is of some use to you.

 

[annka5]

+/- 1C is really not much though, guess if you use the same one consistently it shouldn't lead to much of a prob.
Am actually really surprised they are as accurate as that -I would've guessed at a range of 3C or whatever....

 

[Luke_e]

Thats pretty interesting...

 

[OohFeeshy]

What was the actual temperature?

 

[The-Wolf]

setting on the heater is 28C

 

[Ethos]

Penn Plax; Floating glass thermometer £1.99
shows both C and F, easily broken if knocked accidently.
28C

Thats the one I have.
And even though I am still young, and I dont have/need glasses,m I find it very hard to read the temp without getting up and close to it. Its almost useless when its floating around in my 55G.
But otherwise, just because I can't read it from the other side of the room, it works very nice, and is very cheap.

 

[SirMinion]

Penn Plax; Floating glass thermometer ... easily broken if knocked accidently.

... or bitten by a large, stupid pufferfish who thought it was a snail...

 

[Luke_e]

Wouldn't that poison the fish if it broke?
I saw on the news a family getting charged thousdands of pounds to have their kitchen decontaminated due to mercury all over their kitchen floor after one of them dropped it.

I have a digital, and a mercury one, just to be safe.

 

[SirMinion]

Wouldn't that poison the fish if it broke?
I saw on the news a family getting charged thousdands of pounds to have their kitchen decontaminated due to mercury all over their kitchen floor after one of them dropped it.

I have a digital, and a mercury one, just to be safe.

No mercury in there, the red stuff in the bulb is alcohol, not mercury and luckily Martha didn't break the bulb anyway, just the outer casing containing the bearing weights.

 

[steelhealr]

Funny...except for one thermometer, those all look very close to 28 degrees to me. I would have read the LCD sticker as 28..if you read the directions on the packet on how to read those. Glass is 28. Digital is 28.5 and 28.6. If you were doing a science experiment, you might discard the lowest number. I think the margin of error is really 0.5 without knowing what they each say on the package.

I would MUCH prefer the LCD/digitals vs. straining my eyeballs on a barely visible thermometer. Looking at that one you have there, I doubt you'll really read the temp vs. look for the line to be in the green area. BTW, LCD thermometers are used in the operating rooms to monitor patients body temperatures...they are THAT accurate. I have a Coralife digital thermometer and LCD backup on mine. They are dead on. AT $6 for the digital and $2 for LCD, I think there is a better way. SH

 

[debiasir]

good post The_wolf i choose the glass type as well

LCD thermometers are used in the operating rooms to monitor patients body temperatures

surely they are serious kit though not sub £10 thermometers

 

[The-Wolf]

... or bitten by a large, stupid pufferfish who thought it was a snail...

Thanks Sir M I needed that today

 

[kat and james]

apparently the digital strips (that stick on the outside of the tank) can read the room temperature rather than the tank temperature.. therefore an internal thermometre is better (in my opinion)!!!

 

[StrontiumDog]

Hi Wolf, That doesn't suprise me that Thermometers read different readings.

My work entails weighing out chemicals, I have had this argument with manegment that different scales weigh slightley different weights out than other scales.

In my job managers know best

 

[Synirr]

I just gotta say, it looks kinda comical to see all those different thermometers together in the same place -- like it's crucial that we know the exact temperature of that water down to the tenth of a degree!

The Marina Aqua-minder looks like a good investment for tanks that stand the chance of large temp fluctuations if a heater fails. Luckily we have central heat and air in my house and keep the temp at around 78 degrees F so I don't usually use heaters at all, but I'll definitely have to keep that in mind for when I move next year. Good posting, interesting results!