Thermometers

[brimac41]

I have a new Rena Smart heater and it is giving me fits but I do not think it is the heater . I have a floating and stick on(which I do not care for) thermometers and I wasn't sure about their readings and I can not read them very well so I purchased a digital thermometer . I am trying to make sure the new heater is keeping my tank at a steady temp. but all three are giving me different readings . The floater will say it is a little below 78 degrees , the stick on will say it is between 76 to 80 degrees and the digital will read 79. 5 (give or take a point or two above or below but it stays in the 79 degree range ) .

I purchased the digital so I could read it better due to my eye sight . The digital is a cheap little Zoo Med , it is all my LFS had . Has anyone used this brand and if so can it be trusted for fairly accurate readings ?

 

[jsoong]

The stick on's are pretty much useless, so you may as well ignore that.

The floater at 78 & the digital at 79 is close enough to be the same. Pretty much all instruments will have an error. Most thermometers are +/- 1 degree or so. In a fishtank, you are not really that concerned if it is 78 or 79 .... you just need to be in the ball park.

If you really want an accurate reading, you would need to calibrate your thermometer. Standard method for lab thermometers is to calibrate 0C (32F) with a mixture of ice & water, and 100C (210F) with water boiling at sealevel (correction tables available for altitude).

 

[Raimond]

I have two digital's of the same brand, one on each end of my DT. They are off by 2*. To see if they were the same I put the probes together and sure enough they were 1.5* differant. My chiller is displays another degree higher than the digitals.
I just average the 2 and use the final number.

 

[mfdrookie516]

I have three of the cheap suction on thermometers from walmart in my 150g. They all read the same, which is good. I'm not sure if they are indeed accurate, but like jsoong said, accurate isn't really a necessity. You're looking for a ballpark number and consistency.

 

[brimac41]

For some reason I have become obsessive about the temp in my tank(s) and I can not seem to get past it . I will have to find something new to focus on with my one track mind .

The stick on thermometer has been on my tank(s) since I bought them used from a pet shop that was going out of business and have never removed them , I just don't use them as a guide .

 

[corrado33]

Like was previously mentioned, if you want to know how accurate your digital thermometer is, just boil some water and stick the probe in it. Or put it in a water/ice slushy. It it's one degree off, then just use that adjustment for your measurements.

Before you put the probe in boiling or freezing water though, make sure it's not going to break. Check the range of the thermometer before you do, as it might not be able to measure that high or low.

I personally think you're fine. Temp fluctuates during the day anyway, as it does in nature.

 

[Floyd R Turbo]

This one is my favorite

Aquarium Water Temperature: Coralife Digital Thermometer

$10, I thought it was $8 at one time, most good LFS carry them for $10-12

 

[HUKIT]

This one is my favorite

Aquarium Water Temperature: Coralife Digital Thermometer

$10, I thought it was $8 at one time, most good LFS carry them for $10-12

I have had terrible luck with those. I have purchased and returned 3 of them for significant temp variations.

Like MFD uses the cheap plastic ones are the only ones I use now.

 

[thincat]

The only other way if you can afford it is to get a Ranco temp. controller. I have my critcal units on that controller with no problems at all. Of course I am on the "Dark Side" of the hobby and we are more Paranoid. Hahaha lol