Which thermometer is correct.

[Jake_the_reefer]

I have 2 thermometers and is marina and the other brand is topfin they are 1° appart from one another. I have a third brand coming in the mail to be the tie breaker but which of these brands would you trust more?

 

[sfin52]

they are so close. Its also possible they are both correct. You can have warm spots and cool spots in the tank. Where my water comes in from my canister is cooler than the rest of the tank. About a degree.

 

[Mastiffsrule]

I am not sure you could tell unless you put in an old style glass mercury thermometer. I don’t thinks those can be calibrated but have not used them. I never really trust those things over the good old reliable glass. I just don’t leave the glass one in in case of breakage.

 

[Jake_the_reefer]

they are so close. Its also possible they are both correct. You can have warm spots and cool spots in the tank. Where my water comes in from my canister is cooler than the rest of the tank. About a degree.

I have them about 1 cm appart in a low flow area just to test if they read differently

 

[sfin52]

I have them about 1 cm appart in a low flow area just to test if they read differently

You can make a glass full of ice and water. That should be really close to 32. From there you cab teat both and see tbe difference.

 

[Jake_the_reefer]

I am not sure you could tell unless you put in an old style glass mercury thermometer. I don’t thinks those can be calibrated but have not used them. I never really trust those things over the good old reliable glass. I just don’t leave the glass one in in case of breakage.

What is the brand of glass you use? I want as accurate as possible!

 

[Jake_the_reefer]

You can make a glass full of ice and water. That should be really close to 32. From there you cab teat both and see tbe difference.

That's an excellent idea

 

[tehmadreefer]

My bet is the 3rd will be something different. Best bet is to do the the ice water

 

[Brett S]

The problem with the ice water test is that just because a thermometer is accurate at 32 degrees doesn’t mean that it’s also accurate at 78 degrees. Honesty if you want something that you know is accurate you need something like this, but it’s not cheap...

Thermco ACC611SSCFC NIST Traceable Factory Certified Glass Spirit Filled Thermometer, Total Immersion, -20 to 110 Degrees C, 1.0 Degrees C Division, 305 mm Length https://www.amazon.com/dp/B01N1X1K2Y/ref=cm_sw_r_cp_tai_m9ddDbQKYESAS

 

[Jake_the_reefer]

The problem with the ice water test is that just because a thermometer is accurate at 32 degrees doesn’t mean that it’s also accurate at 78 degrees. Honesty if you want something that you know is accurate you need something like this, but it’s not cheap...

Thermco ACC611SSCFC NIST Traceable Factory Certified Glass Spirit Filled Thermometer, Total Immersion, -20 to 110 Degrees C, 1.0 Degrees C Division, 305 mm Length https://www.amazon.com/dp/B01N1X1K2Y/ref=cm_sw_r_cp_tai_m9ddDbQKYESAS

I've heard using a digital medical thermometer

 

[Jake_the_reefer]

Ice water results

 

[Brett S]

I've heard using a digital medical thermometer

If you get a quality one, then maybe, but if you go to CVS and spend $4.99 then probably not. The other issue with digital medical thermometers is that they often don’t read less than 90 degrees, which doesn’t help us much since we keep our tanks at 78 or 80.

 

[chefjpaul]

32.4 is what Restaurant and food service use as standard as that's correct.

 

[Jake_the_reefer]

If the first thermometer is correct, then is 81 daily high and 79.4 night low acceptable? Or should I reduce the heat. I use fan cooling

 

[Jake_the_reefer]

I do have lps and some softies in this tank with no intention for sps (at least for now)

 

[Mastiffsrule]

I am voting marina based on the ice water test done


Wait for about three minutes before inserting the sensor on the thermometer into the ice-filled water. Wait for about thirty seconds and check that the thermometer reads 32°F. If it does, then it is accurate, but ifnot, it requires calibration.

 

[Jake_the_reefer]

I am voting marina based on the ice water test done


Wait for about three minutes before inserting the sensor on the thermometer into the ice-filled water. Wait for about thirty seconds and check that the thermometer reads 32°F. If it does, then it is accurate, but ifnot, it requires calibration.

After 5 mins marina read 32.4° and topfin read 28°

 

[Mastiffsrule]

Your temps are fine. Lot of tanks run 81 or 82 with you stock. Main thing is staying away from large sudden temp shifts

 

[sfin52]

I would trust marina and I'm not sure you can calibrate those.

 

[Jake_the_reefer]

Your temps are fine. Lot of tanks run 81 or 82 with you stock. Main thing is staying away from large sudden temp shifts

How big of a temp shift would you say is too much in a 24 hr cycle for me it's a 2 to 3 degree shift over 24 hrs every day for about 4 months now and no signs of stress thankfully