But can you TRUST it?

prop-frags

prop-frags

SPS Slave
We recently moved to a new house. Gave us a great excuse to build a new system, and we upgraded from our 125 reef to a 180 setup. With the sump in the garage, temperature swings became a concern, and all our gear is now remote. We placed several different digital thermometers around the place: in the display, in the sump, etc. All were giving different readings. In a hobby where a few units means a lot, we became concerned about the accuracy of this gear. How do we TRUST what these devices are telling us? What's the REAL number? I guess it's all relative; if we've been keeping a certain measurement or parameter at a certain value, and it's stable, and the system is doing well, isn't that enough? Maybe, but it was still keeping me up at night wondering about the values that we all share with one another and that become "generally accepted standards".

We decided to address the temperature issue by purchasing a lab-grade sensitive thermostat:
45277-00.jpg

and then using it to calibrate all the others.
I can post the details if anyone is interested in which of our many thermometers was "correct". Anyway, I thought this was an interesting topic about accuracy of our readings of important parameters. I am curious what other SPS keepers think...
 
I have the same problem. I have 3 dgital temp readouts (Aquacontroller 3, Ranco controller, Pinpoint wireless temp) and they are all different. Who's to say that you can trust the lab grade thermostat as well?:)
 
Take the lab grade thermometer and soak it in an ice bath for a while. It should read 32 degrees and then you can calibrate your other devices based on how far off the lab grade thermometer is.

Chris
 
I figure it is pretty reletive as long as you are stable at a temp you should be fine. within reason.
 
FWIW, I have a titanium-probed lab grade thermometer that is calibrated, and I checked a bunch of thermometers around here - a friend's little $8 coralife was spot on, but i have the same model and mine was 3 degrees low.
 
I have different reading on all of my thermometers. I calibrated my controller's probe using a lab grade probe and am able to work out the differences of the others based on the controller now.
 
The most accurate (or should I say closely matching) thermometer I had to the new hannah unit was old trusty rainbow lifeguard:
RB270779X.jpg

This unit was within 0.5 degrees F.
Others that I had that were 1-4 degrees off:
* Neptune AC Jr (but this is adjustable)
* Pinpoint wireless
* Coralife mini digital

I guess my point in this was more than just temperature or thermometers. The same concern applies to test kit results, pH meters/controllers, ORP, PAR, Kelvin... the list goes on and on. We base a lot of our advice and decisions upon this data that seems so...well, uncalibrated. It may not be worthwhile to be concerned about it, but I am going to take a more critical look at what "numbers" are getting tossed around on this board and in my discussions with local reefers, too.
 
The one above is WAY off for me. My tank on 2 others read 81 and the lifegard read 86.6. When mine hits 82, it says it is 84 and at 84 it is 87. My friend bought one also and his was opposite. His tank was always 76 to 77 and I never understood why because it didn't feel that cold. We both bought the corallife ones and been very consistent since.

Not to mention why any company would put INSIDE temperature for your outside temp. And the Outside temp on the thing for your tank water temp. The designer should be shot. My wife called me once when I had that and said the temp is showing 89. I almost freaked. Finally I asked her what she was reading. She said the inside temp which would be normal however that was the air in the stand which apparently gets hot.

My air reading of it also was off.

I guess each can screw up.
 
the thermometers are actually ment to be mounted by a door and the probe mounted outside. the "inside temp" is ment as inside your house and the "outside temp" is ment as outdoors.
 
always thought about this issue too cuz my chiller reads 82 while my thermometer in the tank will read 79 which i thinkis more accurate since its a real thermometer
 
I have three of the same type (all Little Temp) and they all read different, with a 4 degree range. That's disappointing.
 
You should purchase temperature gages that allow you to calibrate them. Then take a glass and fill it with ice, add cold water and stir it for a minute or so, put the temp probe in the water and it should read just about 32F. If it is off, calibrate it to 32F. Once you have one probe that is accurate you can calibrate the rest or at least know how much to compensate.

You should do this once a year IMO.
 
I think the lifeguard one does.

I know that medusa does (expensive as it's a controller as well) so does the Aquacontroller.
 
the thing is...you only know for sure if you send in that RTD once a year for a calibration...I can do it at work w/ an NIST traceable temperature reference. All temperature measuring devices drift over time...Lab grade or not.

like mentioned above: the ice water bath can get you a decent low point calibration that would probably be good enough for this application, however you should calibrate at a high point as well...

32F - ice water
http://www.biggreenegg.com/boilingPoint.htm - boiling water

i would only trust a 1 point calibration at 32F if i was going to only be using it to measure temp around there. Do a 2 point and you are good anywhere in between
 
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