Glass Thermometer Accuracy

After opening up the thermometer, I found water in the battery chamber and the battery corroded from the water... not so submersible after all...

 

Those things are junk yes. Like everything they make.

 

I use these,
https://banggood.app.link/D2sMdmCjIW
and these,
https://banggood.app.link/LEoFftEjIW

They are cheap and quite accurate. The fist one is quite fancy in that you can setup the variance. So I take a thermometer that I know is accurate and calibrated properly and use it to calibrate this one. Just one tip, keep the probe as far as possible from the heater and make sure the heater is in a water flow to make sure that the heated water is distributed equally around the tank, that way you get a good reading of the overall water temp. Specifically in large tanks. Smaller ones might not make that much difference.

I use the cheap glass thermometers from the LFS simply as a guide to get an idea and make sure the water is not below 25 and not over 30.

 

@David Kusner thats the type I would probably get next, probe only in the water.

 

I have a couple of the first one. It's actually a thermostat relay that's meant to turn on/off stuff. I bought it to control a DIY chiller I'm working on.

I also use a thermometer gun for some random hobby applications. Something like this - https://banggood.app.link/C4rTUw2BrY

It has been fairly accurate. Maybe it has some use for the aquarium hobby too? Instant reading, and the ability to use just one thermometer for multiple tanks, could be an advantage.

You could use the thermostat relay to make a buzzer/alarm that goes off when the temperature peaks towards the high end.

I'm not sure what fish you have but, most tropical fish would do okay (short term) at temperatures at or even over 30 degrees. Inverts, like shrimp, may not survive at those temps. You may want to invest in a chiller like this one to keep those guys alive -
https://banggood.app.link/zPWcggIDrY





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