New APEX Temp probe is off by 1 degree

Jyetman · 07/04/2015, 01:13 PM

So I bought a new temp probe for the PM2 module. Getting ready to setup a salinity system. Before my COND probe comes in next week I'm installing this new temp probe but its reading 1 degree higher then the original temp probe why? Won't this effect the salinity reading? What do I do what a few days?

JAustin · 07/04/2015, 01:28 PM

calibrate it. I recommend checking it against a mercury thermometer or to another reliable temperature reading devise.

Jyetman · 07/04/2015, 01:50 PM

Only thing I can find to calibrate at the moment is a medical digital thermometer will this work?

mmn · 07/04/2015, 02:00 PM

Quote:

Originally Posted by Jyetman

Only thing I can find to calibrate at the moment is a medical digital thermometer will this work?

Yes it will. You can calibrate it to anything. The question is how accurate is the thing you calibrate it to. Why not just calibrate it to your other probe, if you think that it is accurate?

sleepydoc · 07/04/2015, 02:44 PM

+1 calibration is only as good as the reference. Does 1º really matter, anyway?

Jyetman · 07/04/2015, 04:19 PM

If so many are having trust issues with their apex salinity probes why wouldn't the temp probes be the culprit? I mean two apex probes supposedly factory preset have variations of 1 degrees is that a lot to trust to a properly calibrated COND probe? If the TEMP probe isn't calibrated right wouldn't that explain why so many have issues calibrating the COND probes?

slief · 07/04/2015, 06:01 PM

Quote:

Originally Posted by Jyetman

If so many are having trust issues with their apex salinity probes why wouldn't the temp probes be the culprit? I mean two apex probes supposedly factory preset have variations of 1 degrees is that a lot to trust to a properly calibrated COND probe? If the TEMP probe isn't calibrated right wouldn't that explain why so many have issues calibrating the COND probes?

1 degree won't make any difference in the salinity reading. Especially since you should be calibrating the CondX probe using the PM2 temp probe in conjunction with calibration fluid that is the same temp as the tank water. That process alone will insure your conductivity readings are accurate despite the temp variance.

Also, those of us that use the conductivity probes with our Apex generally don't use it to check our salinity. Instead we use it for trends, fail safes for things such as our ATO's & our auto water changes. We use refractometers to measure our actual salinity.

mmn · 07/04/2015, 06:50 PM

And besides, you're not calibrating the probe. You are calibrating the system to a known standard.

n2585722 · 07/05/2015, 06:10 AM

Jyetman, 1 degree is pretty close. Besides there are no two probe that are exactly alike. There is tolerences for them. I assume from the comments that it can be calibrated on the Apex if it is too far off to suit you. I am not familiar with the Apex temp calibration but if it is a single point calibration you will only be accurate at the calibration point. There will be a difference in the reading that will be greater the futher you get from the cal point. A two point calibration will be more acurate within the range between the cal points, but the readings will still be slightly different. Remember these are made to fit within the budget of the hobbist. The more accurate you make things to be the cost can skyrocket quickly.

Also probes are not calibrated. The electronics in the controllers is calibrated to the probe. In the case of the temp probe the electronics is calibrated to the center of probe tolerence. This should be fine for us hobbist.

07/04/2015, 01:13 PM	#1
Jyetman Registered Member Join Date: Nov 2012 Location: Phoenix, AZ Posts: 1,712	New APEX Temp probe is off by 1 degree So I bought a new temp probe for the PM2 module. Getting ready to setup a salinity system. Before my COND probe comes in next week I'm installing this new temp probe but its reading 1 degree higher then the original temp probe why? Won't this effect the salinity reading? What do I do what a few days?

07/04/2015, 01:28 PM	#2
JAustin Acropora Nut Join Date: Jul 2008 Location: Oklahoma City Posts: 1,628	calibrate it. I recommend checking it against a mercury thermometer or to another reliable temperature reading devise. __________________ 211g Planet Aquariums Hybrid PVC bottom 48"x34"x30" and steel stand from CustomReefCreations - Reeflo Super Dart - OM 4way - SRO XP3000 External - ATI Dimmable 8x54w - Apex.

07/04/2015, 02:44 PM	#5
sleepydoc Registered Member Join Date: Oct 2011 Location: Minneapolis, MN Posts: 3,907	+1 calibration is only as good as the reference. Does 1º really matter, anyway? __________________ ~~~~~~~~~~~~~~~~~~~~~ 120 gallon, coast to coast overflow w/beananimal overflow. Waveline DC 10000 II return pump, 40 gal sump, Octopus XS200 skimmer, T5 lighting

07/04/2015, 06:50 PM	#8
mmn Registered Member Join Date: Dec 2013 Location: Fort Lauderdale Posts: 340	And besides, you're not calibrating the probe. You are calibrating the system to a known standard. __________________ Regards Michael 125g DT, Jebao DC9000, BA drain, 55g sump, Mixing: 2x32g Brutes, Panworld 30PX, 20l QT, RLSS R6I skimmer, 3 x Kessil A360WE, Neptune Apex. Current Tank Info: 2 clowns, 2 blue-green chromis, 2 Duncans and 2 GSPs

07/05/2015, 06:10 AM	#9
n2585722 Registered Member Join Date: Aug 2008 Location: Cedar Park, Tx Posts: 1,072	Jyetman, 1 degree is pretty close. Besides there are no two probe that are exactly alike. There is tolerences for them. I assume from the comments that it can be calibrated on the Apex if it is too far off to suit you. I am not familiar with the Apex temp calibration but if it is a single point calibration you will only be accurate at the calibration point. There will be a difference in the reading that will be greater the futher you get from the cal point. A two point calibration will be more acurate within the range between the cal points, but the readings will still be slightly different. Remember these are made to fit within the budget of the hobbist. The more accurate you make things to be the cost can skyrocket quickly. Also probes are not calibrated. The electronics in the controllers is calibrated to the probe. In the case of the temp probe the electronics is calibrated to the center of probe tolerence. This should be fine for us hobbist. Last edited by n2585722; 07/05/2015 at 06:19 AM.

07/04/2015, 01:50 PM	#3
Jyetman Registered Member Join Date: Nov 2012 Location: Phoenix, AZ Posts: 1,712	Only thing I can find to calibrate at the moment is a medical digital thermometer will this work?

07/04/2015, 04:19 PM	#6
Jyetman Registered Member Join Date: Nov 2012 Location: Phoenix, AZ Posts: 1,712	If so many are having trust issues with their apex salinity probes why wouldn't the temp probes be the culprit? I mean two apex probes supposedly factory preset have variations of 1 degrees is that a lot to trust to a properly calibrated COND probe? If the TEMP probe isn't calibrated right wouldn't that explain why so many have issues calibrating the COND probes?