Thermometers, whats the deal?

[da1jewfish]

Any recomendations on brands.
I have 3 thermometers... none being aquarium therms, but they can read under water.
well I have the standard inexpensive ones that stick to or hang on the tank-mercury- it reads 76 F
while one other digi reads 79.7F
and the other reads 81.1
I looked for a calibratable therm but couldn't find any.
I have always trusted the mercury $3 therms, am I wrong?
This is pretty mest up

 

[Henry Bowman]

I am a professional Chef and understand your frustration. You have to buy a decent thermometer to get accurate readings. Best way to test is to take your thermometers and drop them into a mixture of ice and saltwater (not necessarily from your tank, you can use tablesalt.) This solution will get the water as close to freezing as possible and maintain a liquid state. Then read the thermometers. Average and or be aware of their variances.

I check my thermo's that I purchased for my tank
( they dont go down to 32 F) by calibrating one of my good kitchen thermometers and check the tank temp with it to see how close my tank thermo is. I have 1 (one) that is on a hygrometer that is pretty close to dead on, the others I have purchased have been off as much as 5 degrees.

Two most important things, IMO, keeping the temp as steady as possible and not letting it get above 82 deg.

 

[pjf]

Miller & Weber Liquid Thermometers

Miller & Weber Liquid Thermometers

I highly recommend liquid-in-glass thermometers by Miller & Weber (www.millerweber.com) for calibrating temperature controllers and heaters. The foot-long models that I have used have a range from 66 to 80 degrees Fahrenheit which is ideal for aquarium use. Their 0.2 degree increments are spaced a millimeter apart and are easy to read. The mercury-based A20 model is available from www.sealifesupply.com for $24. The T-4900 model is pricier but has a non-toxic blue liquid and is available over the counter from Miller & Weber. I use these to periodically correct drift on my Medusa HC-150 controller and on my Eheim Jager heater.

 

[da1jewfish]

thanks... what are some other recomended brands and styles

 

[pjf]

Calibrate to 0.1 Degrees

Calibrate to 0.1 Degrees

I’m embarrassed that you do not have a better response to your query. Everyone uses temperature controllers or thermostatic heaters but few seem to have an accurate liquid-in-glass thermometer for calibration. Nearly all electronic thermostats and digital thermometers drift.

Here are my criteria when shopping for a calibration thermometer:
• Liquid in glass
• Traceable to NIST (National Institute of Standards and Technology)
• Standard temperature range (77° F or 25° C)
• Easy to read (at least 0.2 degree increments, 1 mm apart)

The 0.2 degree increments are sufficient for calibration to the tenth of a degree. If the increments are a millimeter apart, you can consider the midpoint between the increments to be the odd tenth of a degree.

Aside from Sea Life Supply (www.sealifesupply.com), I know of no other calibration thermometer retailer in aquaria. The 12-inch long A20 mercury thermometer costs $24. It is made by Miller & Weber in Queens, New York. If you shy away from mercury, Miller & Weber makes the near-identical T-4900 thermometer with a non-toxic bright blue liquid. Because Miller & Weber does not have a retailer in my state, I picked up the pricier (~$50) T-4900 during a stopover at the La Guardia airport.

If anyone else has a thermometer used for calibration, please post!

 

[rick s]

I use the Tropic Marin bulb type thermometer.
It's accuracy is advertised as +/- 0.2 degrees.
German made.
It uses a reef safe liquid (in case you break it).

I have 2 of them and they read identically to each other.
I use them to see how much my big, easy-to-read digital thermometer is off.
http://www.aquariumguys.com/thermometer1.html