How I Fixed my Apex Salinity Probe

[AKL1950]

Okay, this may seem a little unusual, and I’m sure there will be some nay sayers, but it seems to have worked And I’m going with it far a while.

It seemed that no matter where I put the probe in the sump, the air bubbles would find it. Even my return pump area has lots of micro bubbles that seem to make the readings go way up or way down. Bubbles in the return pump area are because my UV pump pulls water out of the skimmer area and returns the water to the return pump area causing bubbles to show up there.

I did two things. First I recalibrated the prob with tank water. My salinity is 34.6, so I accepted that as close enough. Still, the air bubbles were making the readings go high. So, my sump water level is 9”. I got a tall kitchen glass that’s 7” tall, put it in the return area of the sump, recalibrated again and put the prob in the glass. Bubble problem solved. Now some might think that there is not enough flow down in the glass, but it does fluctuate as thing in the sump change. It has stabilized a little below what my Hanna and refractometer show, but it is running stable now.

on the first picture, I had recalibrated with tank water on 10 Aug, but the numbers kept creeping up from the air bubbles. On 14 Aug I recalibrated with tank water again and put the probe in the glass. Numbers stable.

second picture shows a 24 hour cycle. The two high peaks are are when I feed and turn off the pumps which changes the sump water level. I think the low marks coincide with the ATO dumping RO water in the return area of the sump.

Third picture is my probe in the glass.

okay nay sayers. See any thing wrong with this technique?

Jetson

 

[Jeffcb]

Okay, this may seem a little unusual, and I’m sure there will be some nay sayers, but it seems to have worked And I’m going with it far a while.

It seemed that no matter where I put the probe in the sump, the air bubbles would find it. Even my return pump area has lots of micro bubbles that seem to make the readings go way up or way down. Bubbles in the return pump area are because my UV pump pulls water out of the skimmer area and returns the water to the return pump area causing bubbles to show up there.

I did two things. First I recalibrated the prob with tank water. My salinity is 34.6, so I accepted that as close enough. Still, the air bubbles were making the readings go high. So, my sump water level is 9”. I got a tall kitchen glass that’s 7” tall, put it in the return area of the sump, recalibrated again and put the prob in the glass. Bubble problem solved. Now some might think that there is not enough flow down in the glass, but it does fluctuate as thing in the sump change. It has stabilized a little below what my Hanna and refractometer show, but it is running stable now.

on the first picture, I had recalibrated with tank water on 10 Aug, but the numbers kept creeping up from the air bubbles. On 14 Aug I recalibrated with tank water again and put the probe in the glass. Numbers stable.

second picture shows a 24 hour cycle. The two high peaks are are when I feed and turn off the pumps which changes the sump water level. I think the low marks coincide with the ATO dumping RO water in the return area of the sump.

Third picture is my probe in the glass.

okay nay sayers. See any thing wrong with this technique?

Jetson

I had the same issue. After apex tech support admitted that they are not that stable. I just calibrated mine in the tank water. The alarm stopped after I relocated the probe to a low flow area on my refugium.

Looks good to me. If its in any kind of flow it fluctuates quite a bit.

 

[Superlightman]

It fluctuate all time.. A shame for such an expensive tool!

 

[Randy Holmes-Farley]

You mention air bubbles make the reading go high? Is that what you meant? Not during calibration, but during regular use?

I’m not seeing how air bubbles can increase the conductivity between the electrodes.

 

[AydenLincoln]

I bought a salinity stabilizer and it fixed all my issues.

 

[Aspect]

I bought a salinity stabilizer and it fixed all my issues.

Link? I would love one of those. This probe by itself is basically worthless which is sad for how much I paid for it!

 

[jsker]

I would suggest to get a prob holder, instead of the prob sitting on the bottom. This will give you more flow around the probe. Second, I stop using my salinity probe as a measure, instead I watch and see if I have a jump or a decline in salinity.

If is have a fluctuation I use my bench top salinity check to really see were I am at.

 

[AydenLincoln]

Link? I would love one of those. This probe by itself is basically worthless which is sad for how much I paid for it!

SPS Kit – The Salinity Probe Stability Kit | Vivid Creative Aquatics

vividcreativeaquatics.com

 

[AKL1950]

You mention air bubbles make the reading go high? Is that what you meant? Not during calibration, but during regular use?

I’m not seeing how air bubbles can increase the conductivity between the electrodes.

No, not during calibration. once calibrated it was very erratic. Also, when I used the Neptune calibration fluid for 35 ppt, it would read above 38 in the sump, so I just calibrated with tank water that I know is about 34.6. That’s using Hanna checker and refractometer. After that, no matter where I put it in the sump, the salinity would creep up to 38 or down to 31. Had to be bubble getting in the prob and messing up the readings. Shake the prob to get the bubbles out, then it would be correct for a bit, then get erratic again. It was constantly going high or low. I put it in the glass and it became stable very close to the real salinity.

 

[AKL1950]

Also, that’s why the holes are on the sides of the probe to let the bubbles out, but they don’t work real well. I suppose if it’s trying to get a reading through air versus saltwater, the reading are going to be messed up. Neptune says that will happen..

 

[Superlightman]

The salinity probes go up and down all the time, I don't think it is only a bubble problem. I think I will try in a glass,so sure they are no bubble and let see if the readings change

 

[Randy Holmes-Farley]

No, not during calibration. once calibrated it was very erratic. Also, when I used the Neptune calibration fluid for 35 ppt, it would read above 38 in the sump, so I just calibrated with tank water that I know is about 34.6. That’s using Hanna checker and refractometer. After that, no matter where I put it in the sump, the salinity would creep up to 38 or down to 31. Had to be bubble getting in the prob and messing up the readings. Shake the prob to get the bubbles out, then it would be correct for a bit, then get erratic again. It was constantly going high or low. I put it in the glass and it became stable very close to the real salinity.

A bubble can decrease apparent salinity, and make it erratic, but not increase it above what it would read without a bubble.

Temperature seems to be a problem with some controllers, both when it is calibrated and when it self correcting for temp changes in the tank. Some folks have the self correction turned off and some have it set to the wrong value. If salinity changes in time with temp changes, that’s a sign that the correction is set wrong.

 

[Randy Holmes-Farley]

The salinity probes go up and down all the time, I don't think it is only a bubble problem. I think I will try in a glass,so sure they are no bubble and let see if the readings change

Up and down on a daily cycle with temperature?

 

[gbroadbridge]

Okay, this may seem a little unusual, and I’m sure there will be some nay sayers, but it seems to have worked And I’m going with it far a while.

It seemed that no matter where I put the probe in the sump, the air bubbles would find it. Even my return pump area has lots of micro bubbles that seem to make the readings go way up or way down. Bubbles in the return pump area are because my UV pump pulls water out of the skimmer area and returns the water to the return pump area causing bubbles to show up there.

I did two things. First I recalibrated the prob with tank water. My salinity is 34.6, so I accepted that as close enough. Still, the air bubbles were making the readings go high. So, my sump water level is 9”. I got a tall kitchen glass that’s 7” tall, put it in the return area of the sump, recalibrated again and put the prob in the glass. Bubble problem solved. Now some might think that there is not enough flow down in the glass, but it does fluctuate as thing in the sump change. It has stabilized a little below what my Hanna and refractometer show, but it is running stable now.

on the first picture, I had recalibrated with tank water on 10 Aug, but the numbers kept creeping up from the air bubbles. On 14 Aug I recalibrated with tank water again and put the probe in the glass. Numbers stable.

second picture shows a 24 hour cycle. The two high peaks are are when I feed and turn off the pumps which changes the sump water level. I think the low marks coincide with the ATO dumping RO water in the return area of the sump.

Third picture is my probe in the glass.

okay nay sayers. See any thing wrong with this technique?

Jetson

You need to have the temperature probe in the same glass. lol
EC probes use the temp probe to correct the salinity.

If you have wildly varying salinity measuresments you need to consider both the EC probe and the temperature probe, both of which can cause issues. They both need to have the same flow of water.

 

[AKL1950]

A bubble can decrease apparent salinity, and make it erratic, but not increase it above what it would read without a bubble.

Temperature seems to be a problem with some controllers, both when it is calibrated and when it self correcting for temp changes in the tank. Some folks have the self correction turned off and some have it set to the wrong value. If salinity changes in time with temp changes, that’s a sign that the correction is set wrong.

Great Randy. What you are saying makes since of what was happening. When I would calibrate with the Apex calibration fluid, it would say my salinity was over 38 ppt. Over a few days, it would gradually decrease to 31 ppt. (Air bubbles). Shake the probe and it jumps back above 38 and then slowly starts dropping again. When I used tank water for calibration, I feel it calibrated correctly. The calibration matched up with my Hanna and refractometer. When I put the probe in the glass, it quit dropping from air bubbles And remained very stable.

 

[gbroadbridge]

Great Randy. What you are saying makes since of what was happening. When I would calibrate with the Apex calibration fluid, it would say my salinity was over 38 ppt. Over a few days, it would gradually decrease to 31 ppt. (Air bubbles). Shake the probe and it jumps back above 38 and then slowly starts dropping again. When I used tank water for calibration, I feel it calibrated correctly. The calibration matched up with my Hanna and refractometer. When I put the probe in the glass, it quit dropping from air bubbles And remained very stable.

I'd suggest making a DIY calibration fluid and checking against that.

It is simply table salt and water and the specifics can be found here:

https://reefkeeping.com/issues/2004-06/rhf/index.php

You cannot use the same calibration fluids for refractometers and EC probes as they work on different principles.

 

[AKL1950]

I'd suggest making a DIY calibration fluid and checking against that.

It is simply table salt and water and the specifics can be found here:

https://reefkeeping.com/issues/2004-06/rhf/index.php

You cannot use the same calibration fluids for refractometers and EC probes as they work on different principles.

Well, I think I’ve pretty much got it working like I want. I’m pretty confident in what my salinity is. It’s all in the math. So much water at temperature x with so many pounds of salt = salinity y. After I mix, all my testing options show what I expected to get which is just below 35 ppt. Now that I fixed the bubble problem, the Apex is agreeing with the other testers, so life is good.

 

[Enderg60]

SPS Kit – The Salinity Probe Stability Kit | Vivid Creative Aquatics

vividcreativeaquatics.com

FYI if you have a 3d printer.

Neptune Systems Salinity Probe Accurizer by Brofessor2507

EDIT: I HAD AN ISSUE WHERE THE PROBE STARTED SLIPPING WHILE IN USE. I ENDED UP GIVING THE ACCURIZER MORE SURFACE AREA TO HOLD ONTO THE PROBE. Sorry about this guys, I guess this is a work in progress. V2 is the latest version, please download and replace the previous version. Also note that I...

www.thingiverse.com

Im going to print one and try it out.

 

[gbroadbridge]

Well, I think I’ve pretty much got it working like I want. I’m pretty confident in what my salinity is. It’s all in the math. So much water at temperature x with so many pounds of salt = salinity y. After I mix, all my testing options show what I expected to get which is just below 35 ppt. Now that I fixed the bubble problem, the Apex is agreeing with the other testers, so life is good.

My only suggestion would be to test against a known reference standard.

You can get a Hanna NIST traceable standard for a couple of bucks.
When I make DIY solutions for my Hanna, I use that as a sanity check.

 

[BZOFIQ]

I bought a salinity stabilizer and it fixed all my issues.

Is that sold in the same isle as blinker fluid?