EMERGENCY: HEATER MALFUNCTION (PLEASE HELP)

[Vincerama2]

Time to borrow the club's calibration thermometer! In fact everyone should probably double check their primary heaters and probes every year:
https://www.bareefers.org/forum/threads/borrowing-the-club’s-calibration-thermometer.25922/

That's cool!

I currently have the club's CO2 meter, which actually has temperature and humidity on it as well.
I took the digital thermometer out of the water and put it's probe next to that device, I also have another desktop humidity/temp gadget that I use to check humidity downstairs I put that next to the CO2 meter as well. The CO2 meter and the humidity meter are within 0.1 degrees F of each other, the aquarium digital thermometer was almost a degree colder reading! This somewhat tracks with what the Ranco controller was giving as a temp, but it has no decimal places.
I think if I use the Ranco, I can get within a degree, which I think is reasonable enough precision and accuracy for an aquarium. And considering that I've been just looking at the Aquacontroller Jr, which was 7 degrees off (and relying on the heater's thermostats), I can't do any worse.
As an alternative to the Club reference thermometer, I think an ice-bath or boiling water will be good enough calibration. Since reef temps are usually a range, rather than an exact absolute temperature, I think stability is probably the most important thing here.

v

 

[Vincerama2]

Ranco and Aqualogic are +/- 2 degrees

Ah, thanks. I think targeting 77 or 78 degrees should be reasonable then. Again, I think stability and the temp being "reasonable" is the target. There doesn't seem to be much consensus about what the "right" temperature is, especially with mixed reefs with corals from all different parts of the ocean.

V

 

[Darkxerox]

That's cool!

I currently have the club's CO2 meter, which actually has temperature and humidity on it as well.
I took the digital thermometer out of the water and put it's probe next to that device, I also have another desktop humidity/temp gadget that I use to check humidity downstairs I put that next to the CO2 meter as well. The CO2 meter and the humidity meter are within 0.1 degrees F of each other, the aquarium digital thermometer was almost a degree colder reading! This somewhat tracks with what the Ranco controller was giving as a temp, but it has no decimal places.
I think if I use the Ranco, I can get within a degree, which I think is reasonable enough precision and accuracy for an aquarium. And considering that I've been just looking at the Aquacontroller Jr, which was 7 degrees off (and relying on the heater's thermostats), I can't do any worse.
As an alternative to the Club reference thermometer, I think an ice-bath or boiling water will be good enough calibration. Since reef temps are usually a range, rather than an exact absolute temperature, I think stability is probably the most important thing here.

v

I've chatted with a bunch of people that regularly calibrate equipment in labs and unless you're using a NIST certified source, you're subject to a ton of variability of the devices, the ideal operating ranges of the devices, if it's measuring air vs. water, and how well mixed the sample is etc. Heck even the equipment they regularly maintain can be off by a degree C or more within their annual calibration period.

I'd avoid the ice bath and boiling water methods since they might be well outside the operating ranges of the devices you use, plus we're shooting for a very tight range of ~72-80F vs. the 32F and 212F there. If I was calibrating a freezer or fridge, then the ice bath method is great!