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ptreef
08/29/2014, 11:43 AM
Suggestions for a way to confirm the reading and then calibrate my apex w/o breaking the bank?

My old probe which is 4 yrs old shows: 77.7*
I installed a new one with in a few inches of the other and it reads: 79.5*

that is about 2* difference.
Probes have been in there for 12 hrs now so should be acclimated and reading what they see

alton
08/29/2014, 11:49 AM
See if you can find someone with a meter that has a temp probe to see which is accurate

ptreef
08/29/2014, 12:02 PM
unfortunately I don't know any one with a meter...

mcgyvr
08/29/2014, 12:11 PM
thermometer.. like you stick in your mouth when you are sick.. few bucks at the store..

Or glass of ice water (32 deg F)

ptreef
08/29/2014, 12:13 PM
Yeah someone else just mentioned the ice water thing.
Probably start there and may give one of these a try:
http://www.lowes.com/ProductDisplay?partNumber=73790-56005-IRT207&langId=-1&storeId=10151&productId=3136869&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1#BVRRWidgetID

mcgyvr
08/29/2014, 03:25 PM
Yeah someone else just mentioned the ice water thing.
Probably start there and may give one of these a try:
http://www.lowes.com/ProductDisplay?partNumber=73790-56005-IRT207&langId=-1&storeId=10151&productId=3136869&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1#BVRRWidgetID

the IR devices are highly dependent on the measured surfaces emissivity.
I would not recommend thinking that will be any more accurate or suitable for "calibration" of temp sensors.. They are only suitable for quick "close enough" measurements.
I'd rather rely on a cheap thermometer.

ptreef
08/29/2014, 03:37 PM
Ok. Thanks

kurt_n
08/29/2014, 04:45 PM
Yeah someone else just mentioned the ice water thing.

That's not going to help you. The Apex temp probes aren't good down that low. You might get a reading, but it's not going to be accurate.

Personally, I'd calibrate the new probe so that it reads the same as the old probe. Assuming all is well in the tank, and it's been running at whatever temperature the old probe shows, I'd just stick with that temp and call it good.

Just curious... why are you replacing the old probe if it's still reading fine?

ptreef
08/29/2014, 08:43 PM
The probe is 4 yrs old so I am not sure it is accurate. That's why i am replacing it. Both are almost 2* off from each other. I'd assume the new one is more accurate. But I'd like to confirm somehow.

I thought the same issue with the ice water as the probe being calibrated that low may be to far from what is is supposed to read.

pH probe is 4 yrs old and still seems to work fine!! Calibrated and seems pretty accurate still.

However with the amount of money in my system, a new $30 temp probe and $60 pH probe seems like a good investment/ upgrade.

jduck
08/29/2014, 08:47 PM
Go get a nist thermometer and calibrate both probes.

Reefvet
08/30/2014, 05:44 AM
The probe is 4 yrs old so I am not sure it is accurate. That's why i am replacing it. Both are almost 2* off from each other. I'd assume the new one is more accurate. But I'd like to confirm somehow.


Temp probes don't age or die with age.

American Marine just released a new calibrating thermometer so that you can match an existing temp sensor, free standing or part of a controller. It's 2 degrees off my Apex probe at 78 and 3.2 degrees off at 81. Neither of them are right. One if brand new and the other one if 6 months old. They're both hobbyist grade, inaccurate.

Pick a safe number like 78 and live with it. Nothing in your reef is going to care or grow any differently +/- 2 degrees from 78.

Consistency is what matters.

ptreef
09/03/2014, 11:32 AM
I am going to order up a NIST traceable temp probe just because I want to be closer to accurate than I am now.

Any recomendations for a good one under $100

Found these:

$25
http://www.novatech-usa.com/Products/Digital-Traceable-Thermometers/4042

http://www.novatech-usa.com/Products/Digital-Traceable-Thermometers/4039
$45 acurracy is +/- 1*

this guy is $50 accurate w/in .4*....Seems like a winner

http://www.novatech-usa.com/Products/Pocket-Thermometers/4350