Solution for a finicky salinity probe?

[jgvergo]

I have an APEX and have gone through the salinity calibration a few times. There are times when the salinity value matches very well with my refractometer readings and other times where there are large differences. I'm assuming it is because of air bubbles in the probe, although I can't always get a correct reading by turning the probe upside down under water and gently tapping it to release bubbles.

The other issue is placement of the probe in my sump. I have it located in a place where I can expect the fewest amount of bubbles, but it's not perfect. Has anyone devised a container of sorts that will allow H2O to flow through while minimizing the bubbles that get in?

 

[CodyRVA]

Might sound stupid, but I wonder if you could modify a travel toothbrush container? Drill a hole big enough to place the probe inside, might be worth a shot considering how cheap those things are. Might need to throw a magnet on it assuming it would float. I'm thinking theres another issue at hand if you're having that much trouble with the probe/bubbles. Another thought is, do you need the probe at all?

 

[jgvergo]

Might sound stupid, but I wonder if you could modify a travel toothbrush container? Drill a hole big enough to place the probe inside, might be worth a shot considering how cheap those things are. Might need to throw a magnet on it assuming it would float. I'm thinking theres another issue at hand if you're having that much trouble with the probe/bubbles. Another thought is, do you need the probe at all?

Nice idea Cody! I especially like the cheap aspect . As to your question...Do I need a probe? Answer = "no". Do I want a probe? Answer = "yes", and since I already have it, I want it to work correctly!

 

[CodyRVA]

Nice idea Cody! I especially like the cheap aspect . As to your question...Do I need a probe? Answer = "no". Do I want a probe? Answer = "yes", and since I already have it, I want it to work correctly!

haha no problem. And I figured as much, i'm sure if i had one i would want to use it and have it working properly as well. Let me know how that idea works, not sure exactly what you're trying to achieve, but it seemed like a decent idea?

 

[jgvergo]

As a newbie reefer, I am really trying to nail my water parameters, including salinity. So, having a constant ability to check it at a glance is attractive. I've also toyed with the idea of programming my APEX to select my ATO source based on the reading of the salinity probe. I already have pumps that can send water to my sump from my RO/DI reservoir and from my saltwater mixing reservoir so it's just a simple matter of programming at this point...IF I can depend on the probe reading!

 

[mcarroll]

The little bit of reading I have done and familiarity I have with digital aquatics I would say that salinity probes are known to be more problematic than other types of probes. Did you run into anything in your research that suggested this?

 

[jgvergo]

The little bit of reading I have done and familiarity I have with digital aquatics I would say that salinity probes are known to be more problematic than other types of probes. Did you run into anything in your research that suggested this?

Yes. I have seen a number of posts on Neptune and other forums where people expressed frustration with getting the probes calibrated. I've also seen a number of posts that indicate success.

 

[mcarroll]

I mostly remember how long it took digital aquatics to come out with a salinity probe that they felt was production ready. It was literally vaporware for years before they found/created what was apparently an acceptable product to sell.

I guess I didn't really have a point I just wondered if you had read the same.

Good luck - I hope you do get it working!

 

[jgvergo]

I mostly remember how long it took digital aquatics to come out with a salinity probe that they felt was production ready. It was literally vaporware for years before they found/created what was apparently an acceptable product to sell.

I guess I didn't really have a point I just wondered if you had read the same.

Good luck - I hope you do get it working!

Ah ha. I did not understand that "Digital Aquatics" was a company! I thought you were just referring to the general use of computers in the aquarium hobby. I did mention that I'm a newbie, right?

 

[mcarroll]

Sorry - typing on a small phone keyboard sometimes gives an excuse for bad typing. A little more attention to capitalization on my part would have helped!

 

[blacktippr]

Where is your probe connected to?

Do you have a Temp probe in the same module?

 

[ckozma]

I also had issues with my salinity probe until I got a second temp sensor and hooked it to the PM2 module. I took the probe out and let it completely dry out. I then floated the 53000 solution in the tank for five minutes to let it get to the same temp as the tank water. I tore the corner of the 53000 bag and stuck the probe in, leaving the bag in the tank water so that the temp wouldn't change. Let it sit there for a couple minutes until the reading stabilizes. These instructions for calibration are much better than in the getting started guide.
https://www.neptunesystems.com/downloads/docs/PM2_manual.pdf

 

[CuseReefer]

Ive had all sorts of issues getting mine to cal with the 53000 solution. I ended up just using my tank water and then knowing 35 PPM was my standard value. If it changes from there I know my salt level is off.

 

[jgvergo]

Ive had all sorts of issues getting mine to cal with the 53000 solution. I ended up just using my tank water and then knowing 35 PPM was my standard value. If it changes from there I know my salt level is off.

CuseReefer, I was seriously considering this approach myself! Since I trust my refractometer reading, why not simply adjust the tank water to 35ppt and use it to calibrate the probe. It does away with temperature compensation issues (i.e. floating the small foil bag of 53000 solution). Also, I am never comfortable that I've gotten rid of the bubbles in the probe when I'm using the foil bag. All in all, it seems that calibrating with tank water known to be 35ppt makes a lot of sense and is much easier.

 

[jgvergo]

@Randy Holmes-Farley , Do you have any insight into CuseReefer's suggestion to use tank water to calibrate an Apex conductivity probe? Of course, the assumption is that the tank water has to be carefully set to 35ppt, 1.026 sg before the calibration procedure.

 

[jduck]

I've had issues with calibration, tried 6 times and couldn't get it to read properly in tank. Did digital refractometer, tank eater 1.026. And just calibrated probe in sump.
You may also try using a cup of tank water outside the system. You may have stray voltage. Or being to close to pH probe.

 

[jgvergo]

I've had issues with calibration, tried 6 times and couldn't get it to read properly in tank. Did digital refractometer, tank eater 1.026. And just calibrated probe in sump.
You may also try using a cup of tank water outside the system. You may have stray voltage. Or being to close to pH probe.

What is the issue with the proximity to the PH probe? I have the two probes in the same probe rack. I also have the excess wire from the two probes coiled together along with the ORP and temp probe. You can see the coiled wires behind the 4 probes in this picture

 

[jduck]

Look on the Neptune forums about the salinity probe calibration.

 

[Kungpaoshizi]

When I had an apex I battled with a salinity probe for a good couple years. It would never stay accurate more than a few days. One reason I ditched it and have never considered a salinity probe again.
A pill bottle is one diy though I've seen the most.

 

[jgvergo]

When I had an apex I battled with a salinity probe for a good couple years. It would never stay accurate more than a few days. One reason I ditched it and have never considered a salinity probe again.
A pill bottle is one diy though I've seen the most.

Hmmmm. I will continue to do battle with my probe. I got an old toothbrush holder out and it looks to be a perfect size. I'll let everyone know how it works out.