Brand new salinity probe...still worthless

[Roosterjack]

This will be my third Neptune Systems branded double junction salinity probe in about two years. The first one came with my original Apex and worked acceptably well for about a year, then started giving super low readings despite careful calibration. The second probe replaced the first, and it too was unable to return meaningful data out of the box.

To rule out the port being bad on the Apex unit I purchased a PM2 module, and it didn’t improve the situation at all. I even plugged one into the Apex, one into the PM2, calibrated both, and to my disappointment neither probe was within 10 points of one another and neither was correct.

Fast forward a year, and new tank, new Apex EL, and new probe connected via the PM2. Tank salinity verified using refractometer and Hanna HI98319 as 34.5. What does the probe say, brand new out of the box? 10.1!

Calibrated, reverified tank measure, and still nothing.

I love my Apex(es) and my many modules, CORs, DOS, etc. Would recommend them to anyone.

After spending a ton of money on two new probes, a PM2, and quite a few calibration pouches I am about to declare that the salinity probes are completely worthless.

Caveat Emptor

 

[SuncrestReef]

The most common problem with the Apex salinity probe is bubbles inside the tube. I found that mounting it fully submerged upside down eliminates the chance of bubbles accumulating inside the probe, and mine has been reading consistently for nearly 3 years now. The big dip on this graph was when I was cleaning my sump and the salinity probe was exposed to the air:

Try submerging the probe, tip it upside down under water, then tap it gently to see if any bubbles escape.

I also calibrate it upside down inside a probe storage bottle so no bubbles can interfere with the calibration process. If you don't have a probe storage bottle, you can achieve the same result using a small plastic bag with a rubber band around the probe to hold the calibration fluid while you tip the probe upside down.

 

[Bacon505]

the prob had too many interference and will never be accurate in my experience. It was a waste of money i feel like

 

[FishDaddy]

I never was unable to calibrare mine after several attempts and never used it. From what I've read it could be stray voltage and keep away from other wires etc. I ran it by itself away from other equipment though.

 

[joseserrano]

Same issue. Have several friends with the same issue, no matter the efforts. Kinda just accept it.

 

[Brett S]

The salinity probes can definitely be pretty finicky. They are very sensitive to external electrical interference and you need to make sure the wire for the probe doesn’t run along any other electrical cables.

The other thing I’ve noticed is that a new probe tends to drift for the first week or two that it’s in the water. It’s my believe that this happens as a film of bacteria builds up on the probe. As such I recommend leaving the probe in the tank water for two weeks before you attempt to calibrate it. And don’t clean it with anything that will kill that bacteria film before you calibrate it or you will have the same issue with the probe drifting until the film comes back.

 

[joseserrano]

For the price one pays, I think you would just expect it to work.

 

[Roosterjack]

Can the cable be wrapped in shielding? Not sure how else I could protect it from interference. I suppose I could put the PM2 on a long extension and come from the far side of the tank versus my control cabinet.

Appreciate the input from all...

 

[boacvh]

I actually had similar issue with the calibration and the below procedure I reference from @rkpetersen fixed it for me. The key was the fake step followed by a reboot. Now my probe working again. Worth a try.

Another Apex salinity probe thread. Help please.

Hi. my salinity probe has been working correctly for a year + now. No issues. I decided to give my sump a thorough cleaning and now the salinity probe doesn’t work anymore. It reads in the 60s. I tried recalibration, and it didn’t work either. I tried manual calibration too with the probe in my...

www.reef2reef.com

 

[BiggieJohn]

has anyone ever tried wrapping the probe cable around a ferrite ring, or a clip on ferrite core ? pretty cheap on amazon, might be worth a try if you have problems with interference

 

[Reefacist]

The most common problem with the Apex salinity probe is bubbles inside the tube. I found that mounting it fully submerged upside down eliminates the chance of bubbles accumulating inside the probe, and mine has been reading consistently for nearly 3 years now. The big dip on this graph was when I was cleaning my sump and the salinity probe was exposed to the air:

Try submerging the probe, tip it upside down under water, then tap it gently to see if any bubbles escape.

I also calibrate it upside down inside a probe storage bottle so no bubbles can interfere with the calibration process. If you don't have a probe storage bottle, you can achieve the same result using a small plastic bag with a rubber band around the probe to hold the calibration fluid while you tip the probe upside down.

@SuncrestReef quick questions about this. I bought the probe bottles but do you leave the temp probe out to measure room temp and perform the calibration with room temp? Or do you submerge calibration solution and pour it in the bottle and check very quick? Can you please give a quick step by step...i just wanna give my apex probe one last shot before I give up on it

 

[SuncrestReef]

@SuncrestReef quick questions about this. I bought the probe bottles but do you leave the temp probe out to measure room temp and perform the calibration with room temp? Or do you submerge calibration solution and pour it in the bottle and check very quick? Can you please give a quick step by step...i just wanna give my apex probe one last shot before I give up on it

I float the calibration solution packet in my sump to bring it up to proper temperature, then put it in the probe bottle to calibrate. Since it only takes a few seconds, it shouldn't cool down enough to have much impact on the calibration.

 

[Reefacist]

I float the calibration solution packet in my sump to bring it up to proper temperature, then put it in the probe bottle to calibrate. Since it only takes a few seconds, it shouldn't cool down enough to have much impact on the calibration.

kk ill give it a shot

 

[MrPike]

Salinity probe, the entire fmm module, all the flow sensors and optical sensors are junk. Rest of the system is great, I love it. They just need to focus on quality and not quantity for a while I think.

 

[Clownfishy]

After over a year using my salinity probe, I now have it working in what I can consider to be the best these probes will work. Firstly, I stopped using calibration fluid for the probe. Instead, I got my salt water to 35ppm by using calibrated Hanna salinity checker and also a calibrated refractometer. I then soaked the probe in vinegar for approx 45mins and then cleaned with RO water. I then performed a "Manual" calibration and not the automated calibration (listed in the Advanced tab on the salinity probe). When it prompted me to dry the probe, I shook as much water off the probe as possible and then dried it off with a clean dry cloth. I also set the TC Factor to 3.0 during the test. When prompted to use calibration fluid, I used tank water. Once I completed the test, I adjusted TC Factor back to zero. After 24 hours, my salinity probe was reading 35.1 It does bounce between 34.5 to 35.0 so is certainly not stable but as least I now have the probe to as close as the correct salinity as I have seen in over a year. I would also agree with the statement that bubbles really affect the accuracy.

Hope the this helps

 

[Clownfishy]

After over a year using my salinity probe, I now have it working in what I can consider to be the best these probes will work. Firstly, I stopped using calibration fluid for the probe. Instead, I got my salt water to 35ppm by using calibrated Hanna salinity checker and also a calibrated refractometer. I then soaked the probe in vinegar for approx 45mins and then cleaned with RO water. I then performed a "Manual" calibration and not the automated calibration (listed in the Advanced tab on the salinity probe). When it prompted me to dry the probe, I shook as much water off the probe as possible and then dried it off with a clean dry cloth. I also set the TC Factor to 3.0 during the test. When prompted to use calibration fluid, I used tank water. Once I completed the test, I adjusted TC Factor back to zero. After 24 hours, my salinity probe was reading 35.1 It does bounce between 34.5 to 35.0 so is certainly not stable but as least I now have the probe to as close as the correct salinity as I have seen in over a year. I would also agree with the statement that bubbles really affect the accuracy.

Hope the this helps

Literally as I made this post, my salinity probe dropped to 34.1 for no reason whatsoever!!!

 

[Reefacist]

Ya I just finished using the storage bottle method and get the same numbers. I just ordered the hanna Refractometer and the tropic marine hydrometer. Let’s see what numbers we get. My tanks fairly new and my clowns, goby and shrimps are fine so I don’t mind waiting but I REALLY want to get this right

 

[Reefacist]

Ohh and I also ordered the ati icp test to see the sg they come up with