I run my system at 1.029 [ ! ]
- Thread starter Berlibee
- Start date
- Tagged users None
wpeterson
Active Member
So what does this methodology of salinity calculation tell you? Was the whole exercise of sending your water to Triton moot for the purposes of this thread or did you feel like you now have an authoritative salinity measurement?
Randy Holmes-Farley
Reef Chemist
Staff member
Super Moderator
Excellence Award
Expert Contributor
Article Contributor
R2R Research
My Tank Thread
If you think the Triton method measures the major ions within a few percent (which I do), then it will measure salinity within a few percent, which is fine for confirming salinity measurements.
OP
OP
Berlibee
.Wen Game.
According to the calculation, looks like I really run my system at 1.028 - 1.029 right? It's showing that refractometers are right and the Apex probe is not? 
@Randy Holmes-Farley @JimWelsh
@Randy Holmes-Farley @JimWelsh
jason2459
Not a paid scientist
- Joined
- Jul 28, 2015
- Messages
- 4,668
- Reaction score
- 3,197
Yes, around 1.028. It would not surprise me that the probe is not calibrated right. I also would not depend on the apex probe as it is very susceptible to a lot of interference. My pinpoint salinity (conductivity) monitor is much more reliable. I trust it. I also trust my veegee refractometer and has been my most reliable testing device.
OP
OP
Berlibee
.Wen Game.
But that's mean that it's just impossible to calibrate the probe right. I've calibrated it with so much precision in the process, temperature, light, all conditions with care ... and anyway it's wrong.
I've calibrated it with so much precision in the process, temperature, light, all conditions with care ... and anyway it's wrong.
jason2459
Not a paid scientist
- Joined
- Jul 28, 2015
- Messages
- 4,668
- Reaction score
- 3,197
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.
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.
Last edited:
wpeterson
Active Member
Thanks for posting your data and conclusions. Hopefully this will help the next person struggling with an Apex salinity probe.
I was on the fence about buying one myself, but the wisdom seemed to be that they are too expensive and not reliable.
I was on the fence about buying one myself, but the wisdom seemed to be that they are too expensive and not reliable.
Randy Holmes-Farley
Reef Chemist
Staff member
Super Moderator
Excellence Award
Expert Contributor
Article Contributor
R2R Research
My Tank Thread
FWIW, 36.6 ppt is approximately a specific gravity of 1.0276. That will not hurt corals.
