Apex Conductivity Reading is way off !!

[sunshinereefer]

I installed the Apex Gold Package in Jan 2015. So far things have been working well except for my problems in connecting my radions to the WXM module.

Since last 2 weeks my conductivity reading started going up from 35 to 36 then 37 and ended up at 38 - when I decided to investigate.

1. Checked the reading of my tank with a calibrated refractometer - reading was 35.
2. Dried the probe for re-calibration for 3 hours.
3. Followed the re-calibration process and the reading in the re-calibration solution was 34.9.
4. Add the probe back in my sump the reading drops to 31.
5. Put the probe back in the test solution - reads 34.6.

Waited for a day. Followed the same above steps after drying the probe for longer period of 6 hours. Got exactly same results. My temp compensation is 0.0 and I have carefully cleaned the probe of any debris.

Waited for another 2 days. This time dried the probe for 2 days complete and followed the re-calibration process - exactly same results.

I re-calibrated my refractometer using the same solution I am using to re-calibrate the probe and it reads 35. I have run out of options to fix or troubleshoot this problem. Any help will be greatly appreciated !!

 

[ngvu1]

I notice that temperature has a lot to do with the number reported by the conductivity probe. I have a temp probe on the PM2 and that does not seem to do anything to the temperature calibration feature. BTW, I keep the tank cooler in the winter and warmer in the summer. The probe seems to be more accurate when the temp is about 78 degree. My tank is 76 in the winter so the probe, at least for my case, reports about 32 instead of 33....Besides, I just use it for watching salinity drop or rise continuously; attention needed for the tank .

 

[Sabellafella]

Thats crazy i just had the same prob 1 week ago, it was slowly rising up so i did some crazy research about 2 part, ballist cords, so i recalibrated and just stuckt it back in seems to be fine, the bubbles in the probe are suppost to exit threw the 2 holes, my problem was i would flip yhe probe upsidedown in the tank to get all the bubbles out and pretty sure this is why that happened

 

[sunshinereefer]

I notice that temperature has a lot to do with the number reported by the conductivity probe. I have a temp probe on the PM2 and that does not seem to do anything to the temperature calibration feature. BTW, I keep the tank cooler in the winter and warmer in the summer. The probe seems to be more accurate when the temp is about 78 degree. My tank is 76 in the winter so the probe, at least for my case, reports about 32 instead of 33....Besides, I just use it for watching salinity drop or rise continuously; attention needed for the tank .

Same here - the main reason is to use it to monitor salinity to determine a water change as I wet skim and hence loose a lot of water.. But this thing is driving me nuts

 

[sunshinereefer]

I am not sure how to detect a broken probe - because when I calibrate it shows 34.9 or 35.1 on the apex for a 35 solution consistently but the moment it's back in tank - it's messed up.
As far as temp is concerned - I did recalibrate the temp probe also checked with a digital thermometer and the temp matches on thermometer and apex

 

[mb165]

I've been having the same problem. I have two tanks with conductivity probes that are less than a year old and they worked great when I first set it up but now they refuse to read correctly. They are now off by about ~5 (it's a stable reading so I can just add the difference but I shouldn't have to and it's not useful for automation). I think my probes are bad, but I wont be replacing them due to the sort lifespan and cost.

If you go to the neptune forums, lots of people have issues with them.

 

[bevo5]

Seems to be a common problem and I'm having it as well. Refractometer says 35. Apex says 30. I read something once about changing the temp adjustment up or down to just get the apex to say 35. Then you can just go from there. But that seems like just covering up the issue.

 

[samba_dad]

Throw a grounding probe in your tank and move your PM2 and probe as far away from other electrical equipment as possible. Also, gather up any slack in the probe cable in a loop and put a cable tie around it. This fixed the problem for me. If I had to guess I would think this is due to stray voltage in some of your equipment. Try turning all of your equipment off except for the Apex and see if you get a jump in conductivity towards the correct value. You can also just put the water in a separate cup and put the probe in it. Good luck - frustrating process until you get it solved.

 

[samba_dad]

Also put that temp adjust at 2.0. Find the BRS video on Apex conductivity probe and watch it. Temp is important for accurate conductivity readings. Good luck solving it. You paid a lot for the equipment and I have found it is reliable but just takes a little elbow grease and frustration. Hope it works out for you.

 

[sunshinereefer]

Also put that temp adjust at 2.0. Find the BRS video on Apex conductivity probe and watch it. Temp is important for accurate conductivity readings. Good luck solving it. You paid a lot for the equipment and I have found it is reliable but just takes a little elbow grease and frustration. Hope it works out for you.

Thanks for the advise - will give it a try but I agree this is frustrating if you paid top dollar for this equipment and the new probe costs 125/- but what guarantee do I get that if I buy it new it will last more than few months

 

[sunshinereefer]

Seems to be a common problem and I'm having it as well. Refractometer says 35. Apex says 30. I read something once about changing the temp adjustment up or down to just get the apex to say 35. Then you can just go from there. But that seems like just covering up the issue.

I am relieved that a few other folks are facing the same problem - it left me frazzled that it worked fine for 9 months and then starts acting funny..if it was related to stray voltage or how I have setup this tank and equipment - trust my word nothing has changed in the last 3 months - so if I setup something incorrectly it should not have worked well for nine months

 

[samba_dad]

What happened to me was my Maxspect Gyre power cord cracked after a few months and the conductivity probe issue allowed me to find the problem and get it repaired. Just normal maintenance and time can cause these sorts of problems. I use my conductivity probe to replace water after water changes to maintain exact 35 ppt. However, I check it every week with calibrated refractometer. I wish you well. Let me know if you have any questions and I will try to help.

 

[ngvu1]

So what was the difference in conductivity reading when the "Maxspect Gyre power cord cracked"?

 

[samba_dad]

It jumped several points in salinity. I would read 36-38 ppt depending upon location of probe to Gyre. Small crack in the cord to the motor - widespread problem for early Gyres.

 

[JPK]

I had the same issue with a 10 month old probe. I recalibrated the probe like 6 times (went through a ton of calibration fluid), made sure there were no micro bubbles in the probe, re-aligned the cord, soaked it in diluted white vinegar, etc. still displaying big swings in salinity.

I contacted Neptune and they had me try several different things/settings, which did not work. I finally sent my probe and module into Neptune. They tested it and said the probe was damaged, which I felt was strange since I had always treated the thing like an egg. I purchased a new probe through apex, which was greatly discounted (1/2 price if I remember right).

I hooked up the new probe (with the old module) and everything has been stable/accurate ever since.

 

[sunshinereefer]

I will check for stray voltage in my tank. I have the grounding probe - should I connect it in my tank ??

I will contact neptune and see if they can help me out !! Is there a forum on reef2reef that they monitor ??

 

[JPK]

I contacted Neptune through my fusion interface, upper right on the dashboard. They were very quick to reply.

 

[Sabellafella]

I will check for stray voltage in my tank. I have the grounding probe - should I connect it in my tank ??

I will contact neptune and see if they can help me out !! Is there a forum on reef2reef that they monitor ??

I spoke to then a few days ago about what goes on and they answered with stray voltage and ballist cordss, flow and bubbles will not give an accurate reading

 

[Diesel]

FYI, I have trying to get my probe to work close to perfect but after close to 3 years I just dropped my probe.
Not worth the trouble to go through a lot of magic loops to get the perfect # at 35.
I use two refractor meters and they do fine for me just once a week and in all the cases I never had to adjust my salt level in my tank .
APEX is a great product as I have two full controllers running on the DT and one on the Frag system.
Can't go without it anymore but the conductivity probe is just one of their black sheep's.

 

[jduck]

Worked great for a year. Recalibrated 6 times and can't get it to read 35 in tank water. No matter what I try, you name it. Even in a seperate plastic cup. Grounding probe. I've used Milwaukee digital refractometer and calibrated refractometer to verify tank salinity. So I gave up and calibrated it in tank sump.