A word of advice on thermometers...

[Chris O]

Hi All,

 

Had an experience worth sharing to save some of you a headache. I've been using 2 digital thermometers to monitor the temperature of my nano reef, using each as a cross check. I've noticed the temperature on both could vary by a degree or two and both were constantly reading low. So, I kept cranking the heat up. My heater was basically at full blast when I decided to pickup a regular magnetized thermometer by JW. BOTH DIGITAL THERMOMETERS WERE OFF BY 10 DEGREES. I was roasting my green star polyp at 90 degrees. Sometimes keeping it simple with less tech is the safe way. This definitely explains a lot of problems going on. I hope none of you have the same issue, the thermometers I were using were ordered off of Amazon, do not buy these:

 

https://www.amazon.com/Windbells-Aquarium-Thermometer-Terrarium-Temperature/dp/B07RBPV8Q4/ref=zg_bs_2975477011_5?_encoding=UTF8&psc=1&refRID=0D4E6SHSK9ZWQQVBJQZA

 

Best,

Chris

[Chris O]

Fingers crossed the Green Star Polyp will make a recovery.

[kimberbee]

Sorry you had to learn this the hard way. 

 

It seems that many brands sell that same digital thermometer, with barely any variation between them. I've had up to 5 of them in one tank, and they all read differently!! I now have a couple of floating thermometers that I can rotate between tanks to double check temperature every few weeks. 

[jservedio]

Be careful with those little alcohol thermometers too. They can be just as inaccurate.

 

Your best bet is to check on things periodically with a calibrated instant read kitchen thermometer.

[mcarroll]

For what it's worth, I don't see anything but LCD thermometers for sale in local shops around here.

 

I like them and always use one as a backup, but I don't like be limited to just using them....they are durable and don't lose calibration...but precision is necessarily low....lower than a standard alcohol thermometer.

 

I will also say that after about 10 years I noticed the other day that my old digital thermometer is doing exactly what the OP saw on his cheapie.  Historically this one has read in solidarity with a Reefkeeper probe and an LCD thermometer, but after cleaning it and replacing the battery when I switched it to the new tank setup, apparently that was too much for it.  🤷‍♂️

 

I'd still recommend that thermometer if they still made it tho...it ran flawlessly on one battery for about 10 years straight.....but it looks like Lifeguard has switched to an all-internal design:

LIFEGARD® LED Digital Thermometer

 

They do still make the older-style "Big Time and Temp" which has alarming features (...but I had the smaller one):

LIFEGARD® Digital Thermometer

[05XRunner]

I use 3 cheap digital thermometer, a laser gun and a cooking digital thermometer and take the average of those 4 and call it a day.