Apex COND Calibration Question

Jyetman · 08/01/2016, 01:49 PM

I've had my Cond probe for a year now and nearly 4 months for it to be reliable. Back in December I bought Pinpoint 5300 calibration fluid and today performed another calibration. Before it was 32.4 this time 33.3 with 5300 reading at 36.5 PPT curious I tested 5300 with my Milwaukee MA887 refractometer which reads 36 PPT will the probe be accurate? MA887 shows tank salinity the same as the probe 33 PPT.

slief · 08/01/2016, 03:13 PM

Quote:

Originally Posted by Jyetman

I've had my Cond probe for a year now and nearly 4 months for it to be reliable. Back in December I bought Pinpoint 5300 calibration fluid and today performed another calibration. Before it was 32.4 this time 33.3 with 5300 reading at 36.5 PPT curious I tested 5300 with my Milwaukee MA887 refractometer which reads 36 PPT will the probe be accurate? MA887 shows tank salinity the same as the probe 33 PPT.

The difference in the tests between the Apex reading and the MA887 most likely has to do with the temp compensation or you didn't let it settle long enough. Temp is most likely. The cal solution may not have been the same temp as the tank water where your Apex probe was. That said, the difference between 33.0 and 33.3 is next to nothing (.0002) and not even a concern.

33.0 is 1.0249 vs 33.3 is 1.0251. I'd say your probe is accurate.

jason2459 · 08/01/2016, 03:19 PM

I do not believe you can use the pinpoint calibration solution for the neptune Apex?

http://www.bulkreefsupply.com/neptun...n-53-0-ms.html

FWIW, when I first setup my Apex salinity probe I was getting a good 3ppt swing through out the day and sometimes even up to 5ppt. I just used it as a basic wide range failsafe for my ATO and AWC.

I fixed it by rerouting the cable to the PM2 and the probe, angled the probe away from the slight flow it was getting (no bubbles in the area as well), and recalibrated again with the Neptune calibration packet. I do have a temp probe plugged right into the PM2 as well.

The calibration I did completely different from the first time doing it. Before starting I took the salinity probe out and soaked it in some water/vinegar for a while (~30 minutes), then rinsed very very well with RO/DI water, wiped it down and shook it out a bit to displace any water, and let it sit for about an hour drying out. I placed the 53.0 mS calibration packet in my sump and let it sit in there that entire time adjusting to the tank water temp it's normally at. I also made sure to set the temp Conductivity Compensation in the input setup to 2.2 and range set to salinity before starting the calibration.

Then I started the calibration selecting the 53000. Wait 10 minutes while it's adjusting to the Dry probe. Then I continue. I clipped the corner of the packet to be able to shove the probe in and kept holding it in the water (I did not use the temp probe in the packet just the temp probe was next to it in the sump). I gently swirled it around periodically for around 5 minutes. And then just stood there for another 5 minutes. Making sure to hold the packet closed well around the probe and in the sump water. Then ended the calibration.

My apex probe has been pretty solid since then. It varies now with in 1ppt and I was able to tighten up my failsafes and trust it a bit more. I also shake it a bit periodically in the sump. About once each day or every other day.

Jyetman · 08/01/2016, 03:50 PM

Very informative thanks. How often do you calibrate every six months or once a year?

jason2459 · 08/01/2016, 04:00 PM

It's been at least 6 months since I calibrated mine. I'm due mainly because I switched sump locations, had it unplugged for a few days, and after plugging in it got a lot of interference from a ballast which is now fixed. I would calibrate when it starts drifting.

08/01/2016, 01:49 PM	#1
Jyetman Registered Member Join Date: Nov 2012 Location: Phoenix, AZ Posts: 1,709	Apex COND Calibration Question I've had my Cond probe for a year now and nearly 4 months for it to be reliable. Back in December I bought Pinpoint 5300 calibration fluid and today performed another calibration. Before it was 32.4 this time 33.3 with 5300 reading at 36.5 PPT curious I tested 5300 with my Milwaukee MA887 refractometer which reads 36 PPT will the probe be accurate? MA887 shows tank salinity the same as the probe 33 PPT.

08/01/2016, 03:19 PM	#3
jason2459 Registered Member Join Date: Jul 2009 Location: Iowa Posts: 9,671	I do not believe you can use the pinpoint calibration solution for the neptune Apex? http://www.bulkreefsupply.com/neptun...n-53-0-ms.html FWIW, when I first setup my Apex salinity probe I was getting a good 3ppt swing through out the day and sometimes even up to 5ppt. I just used it as a basic wide range failsafe for my ATO and AWC. I fixed it by rerouting the cable to the PM2 and the probe, angled the probe away from the slight flow it was getting (no bubbles in the area as well), and recalibrated again with the Neptune calibration packet. I do have a temp probe plugged right into the PM2 as well. The calibration I did completely different from the first time doing it. Before starting I took the salinity probe out and soaked it in some water/vinegar for a while (~30 minutes), then rinsed very very well with RO/DI water, wiped it down and shook it out a bit to displace any water, and let it sit for about an hour drying out. I placed the 53.0 mS calibration packet in my sump and let it sit in there that entire time adjusting to the tank water temp it's normally at. I also made sure to set the temp Conductivity Compensation in the input setup to 2.2 and range set to salinity before starting the calibration. Then I started the calibration selecting the 53000. Wait 10 minutes while it's adjusting to the Dry probe. Then I continue. I clipped the corner of the packet to be able to shove the probe in and kept holding it in the water (I did not use the temp probe in the packet just the temp probe was next to it in the sump). I gently swirled it around periodically for around 5 minutes. And then just stood there for another 5 minutes. Making sure to hold the packet closed well around the probe and in the sump water. Then ended the calibration. My apex probe has been pretty solid since then. It varies now with in 1ppt and I was able to tighten up my failsafes and trust it a bit more. I also shake it a bit periodically in the sump. About once each day or every other day. __________________ rebuild and recovery log: No more red house, you'll have to click on my name and visit my homepage! You can check out my parameters at reeftronics dot net website and look for my username. Current Tank Info: 180g mixed reef w/ a beananimal overflow to a dolomite RRUGF. \| 20g long G. Smithii Mantis Tank

08/01/2016, 04:00 PM	#5
jason2459 Registered Member Join Date: Jul 2009 Location: Iowa Posts: 9,671	It's been at least 6 months since I calibrated mine. I'm due mainly because I switched sump locations, had it unplugged for a few days, and after plugging in it got a lot of interference from a ballast which is now fixed. I would calibrate when it starts drifting. __________________ rebuild and recovery log: No more red house, you'll have to click on my name and visit my homepage! You can check out my parameters at reeftronics dot net website and look for my username. Current Tank Info: 180g mixed reef w/ a beananimal overflow to a dolomite RRUGF. \| 20g long G. Smithii Mantis Tank

08/01/2016, 03:50 PM	#4
Jyetman Registered Member Join Date: Nov 2012 Location: Phoenix, AZ Posts: 1,709	Very informative thanks. How often do you calibrate every six months or once a year?