Nate McFin

Long story short...(Ive heard that one before!)
I had a case of ICH with my cardinals several months ago and I turned my heater up to 84. After the Ich cleared up I turned the heater back down to 82as Cardinals prefer warmer water.(82-84 in the wild)
The fish have always been somewhat lethargic and I couldnt figure out why. I recently turned the heater down to 78 to see if that would help things and they perked up and are actively schooling.
Heres the kicker....my heater was set at 78 and my Coralife digital thermometer is reading 80 still. So I checked with my digital kitchen meat thermometer and it reads 84. I checked with a Mercury bathroom thermometer and it still reads 84. So my heater setting is off by 6 degrees and my digital coralife is off by 4. When I had the heater set at 84 it was actually 90! I cant believe they were so far off of each other. Well I now have the tank at what appears to be a true 80. All fish are active and looking great. I wonder now if that might explain the 3 fish I lost for no apparent reason. I wish I had noticed sooner.
Cross check your thermometers and heaters it could save a life. So much for the long story short!)

metal_fish

Unfortunate Experience!!! I had a thermometer that was off by 6, but i just didn't believe how warm the water was I think my finger is a pretty decent thermometer i knew something was wrong and bought a new thermometer.

JBird86

Sorry about your loss yea, Ive never had a heater that was accurate, the ones that are on my tanks now are both at least 4-6 degrees off

Tony G.

wow... that is scary! good thing you noticed too...

mommybaby295

my heater is 4 degrees off, but i have 2 thermometers - a digital and a mercury. hopefully at least one is right

aquarist48

Good morning. It's always good to have 2 thermometers. I place both in my filters which I believe gives a more accurate temperature due to the fact it has flowing water over it. Remember heat rises so the temperature at the bottom of the tank may vary from the temperature a the top of the tank.
Note: Most thermometers are now alcohol based and not mercury based. Especially ones for aquarium use. That is what makes them aquarium safe.
Ken

mommybaby295

Oh, then mine is probably not mercury. Thanks Ken

eiginh

Wow, I'm glad you didn't lose any more fish! Good job on noticing early enough to not kill the rest of the tank mates. Hmm, I also have coral life thermometers... I wonder if mine are giving accurate results. Nate what do you prefer as the better thermometer?

Nate McFin

Honestly from what I have read there arent any unless you want to drop big money. My new game plan is to keep track with multiple thermometers and just watch for changes.
The mercury thermometer (like you use when your sick) was the same as the digital thermometer I use for BBQ's (used to...lol) So I think they were the most accurate but it seems like there is alot of variance between all aqua thermos. One may be accurate the other may be off. Kinda strange in todays world when things get more and more precise that we cant get an accurate temp.

eiginh

Yes, it's weird. With all the touch screens, flat tv's, 3d gaming, advanced in modern technology but not thermometers!

Electricat

I don't think it's technological incapability, I think the issue is price point and sales volume. I suspect there is way more marketability for $3 Made in China thermometers than a high quality piece for $20.

This is an excellent topic to bring to folks attention!! I have always cross-checked my temps, but I grew up around high precision machining, so I naturally tend to check calibration and accuracy of any measuring device.....but most fishkeepers, even careful and attentive ones, I think take it for granted that the products they buy work correctly.....obviously we can't assume this!