Apex Condx probe question

[jimbow]

So I asked this on the Neptune forum and no one has answered so I thought I'd try here.

I know when I set up my Apex I had an option to set the Condx probe to work with the temperature probe on the module. At the time I didn't have a temp probe on that module (long story). Now I do have one attached to the module and I'd like to get it working with the Condx probe. I read the instructions that said to go to the display and set one of the setup parameters to %/C. I tried that but %/C is not an option on the list. Am I missing something or did it set something since I didn't do it at the setup stage? I to have the temp probe set to F but I tried setting it to C and nothing changed.

 

[RayAllen3422]

I did the same thing. I bought new conductivity calibration solution and did it all over again. Since then my readings have been normal. YouTube search bulk reef supply's video on how to calibrate the probe. That's what I followed and it worked great. I'm not sure what the %/C thing is that you are talking about. At least I didn't use it. I checked my with a refractometer as well and it is functioning correctly.

 

[jimbow]

Do you have a temp probe on the module with your condx probe. Maybe that is what I need to do is recalibrate.

 

[RayAllen3422]

Do you have a temp probe on the module with your condx probe. Maybe that is what I need to do is recalibrate.

I didn't when I first got the Apex and calibrated it. My readings were all over the map. I didn't realize you needed a second one for it to be accurate. I bought another temp probe and calibration solution and it has been fine since. IMO the thing is useless without the second temp probe. The readings before provided nothing of value and were clearly wrong.

 

[jimbow]

Mine aren't all over the map it is pretty steady but doesn't match what I get on the Refractometer. I am hoping it gets closer with the temp probe installed. I thought I could just add the temp probe and make them work together but it doesn't seem to work.

 

[RayAllen3422]

No they have to calibrated together. Basically temp fluctuations affect salinity which isn't taken into affect unless you use with the temp probe. You calibrate it with the temp probe. Watch the BRS video it really clarifies things.

 

[jimbow]

OK thanks a bunch.

 

[jason2459]

Copy paste on my experience with the Apex salinity probe from another thread.


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.


Or your probe is bad.

 

[disc1]

No they have to calibrated together. Basically temp fluctuations affect salinity which isn't taken into affect unless you use with the temp probe. You calibrate it with the temp probe. Watch the BRS video it really clarifies things.

Temp fluctuations don't affect salinity. Temp fluctuations affect the conductivity you are using to indirectly measure salinity. They affect specific gravity you might be using to indirectly measure salinity (hydrometer). They affect refractive index which you might be using to indirectly measure salinity (refractometer). But the salinity is measured in weight/weight units so it doesn't change. The actual amount of salt and water is the same no matter the temperature. It's just that you can't directly measure it so we are stuck using methods that do vary with temperature.

 

[RayAllen3422]

Temp fluctuations don't affect salinity. Temp fluctuations affect the conductivity you are using to indirectly measure salinity. They affect specific gravity you might be using to indirectly measure salinity (hydrometer). They affect refractive index which you might be using to indirectly measure salinity (refractometer). But the salinity is measured in weight/weight units so it doesn't change. The actual amount of salt and water is the same no matter the temperature. It's just that you can't directly measure it so we are stuck using methods that do vary with temperature.

That's what I meant. It's basically the ability to measure that fluctuates with temperature.

 

[jason2459]

Temp fluctuations don't affect salinity. Temp fluctuations affect the conductivity you are using to indirectly measure salinity. They affect specific gravity you might be using to indirectly measure salinity (hydrometer). They affect refractive index which you might be using to indirectly measure salinity (refractometer). But the salinity is measured in weight/weight units so it doesn't change. The actual amount of salt and water is the same no matter the temperature. It's just that you can't directly measure it so we are stuck using methods that do vary with temperature.

You mean you don't weigh the evaporated sea water to measure saltness?

[emoji1]

 

[jason2459]

OP once properly calibrated, tied with a temp probe, and positioned to reduce interference the Apex "salinity" probe should be fairly accurate and consistent.

Here's a screen shot from a few minutes ago before I sarcastically posted above. I would not suggest drying seawater and weighing it. It will not provide accurate results.

I'm usually with in .5ppt which is perfectly fine for what I need it for