Salinity probe
- Thread starter mike_dani
- Start date
D
Deleted member 143833
Check for air bubbles. The next time this happens move the probe brisky through the water to clear any air that may have built-up around te probe. These probes prefer a slow water movement area and no air bubbles!
Orcrone
New member
I get the same spikes mike_dani described with the salinity probe, but my ph and temp probes seem to be very steady with no spikes.
D
Deleted member 143833
Other probes like more water movement and are more affected by dirt. If you are seeing spikes on all your probes you might want to check for equipment leaking electrons into the water.
I see spikes in temp and ph, but nothing on ORP. All three are right next to one another in a high flow area with lots of bubbles, though for the most part the immediate area around the probe is pretty low on bubbles. I have a grounding probe in the water. I would think ORP would be more sensitive to electricity leak spikes? No?
D
Deleted member 143833
I haven't seen any data 1 way or the other on which probe is more or less sensitive to electrical interference and I don't run a grounding probe but I wouldn't expect that to cause any issues 1 way or another in most cases. if this was an AC3 I might think otherwise but not with an Apex.
jmchzn123
New member
Temp correction along with calibration? I called Carl and he said yes use temp correction. Set it for 2.1 then calibrate. I moved probe away from pumps in the sump. Also away from other probes. I used Neptune 53000 calibration fluid. Got the fluid to 25c. Have the temp probe in the same space as the COND probe connected to PM2. calibrated w Carl on the phone everything seemed to work. After calibration my salinity was high. Almost 37ppt. So before I panic I measured salinity with my new DD Refractometer (ATC) it's a temp correction seawater refractometer. Calibrated with RO/DI water @ 20c. The refractometer is at 20c as per instructions. The refractometer is reading about 2.1 lower than the probe. Probe is 36.9 and refractometer just under 35ppt. What is going on? Should I recalibrate and forget temp correction. As far as I can tell the temp never fluctuates more than .5 - 1F.
schwaggs
New member
Calibrating your refractometer with RO is not the most accurate method. Many refractometers are quite off around 35ppt when using this method of calibration. To be the most accurate, get yourself some 35ppt calibration solution for your refractometer such as this : http://cgi.ebay.com.sg/35-PPT-REFRACTOMETER-CALIBRATION-SOLUTION-/270370466481
My bet is on the Salinity probe reading being more accurate...
jmchzn123
New member
Well the DD seawater ATC refractometer states RO/DI water should be used and they have a reference point on the scale for it ( Zero @ 20C) . I'm so frustrated that I just bought 35ppt solution. Funny I have some Pinpoint 53000 and that seems to be off as well. But someone said that's for probes not refractometers. But that stuff didn't work on the Neptune probe either unless my watr is like 1.012! Killing me!Calibrating your refractometer with RO is not the most accurate method. Many refractometers are quite off around 35ppt when using this method of calibration. To be the most accurate, get yourself some 35ppt calibration solution for your refractometer such as this : http://cgi.ebay.com.sg/35-PPT-REFRACTOMETER-CALIBRATION-SOLUTION-/270370466481
My bet is on the Salinity probe reading being more accurate...
jmchzn123
New member
OK if thats the case I assume the ATC refractometer should be calibrated at about 68C. The reference fluid temp shouldn't matter. If thats the case my refratometer is calibrated correctly and DD is correct RO/DI water for this unit works. I'm dead on. So now my tank is 35ppt dead on w refractometer and Neptune is a 37.3, TEMP COMP 2.1. I'm going to recalibrate with TEMP probe in the same water as COND probe which has the 53000 solution floating in it overnight. I will leave the the TEMP CORRECTION at 2.1 and see what flies.The Pinpoint 53000 solution can be used to calibrate your refractometer.
You cannot use the Neptune probe calibration solution to calibrate the refractometer however...
sfboarders
New member
I've had my salinity probe jump up like that. Talked to Curt about it for a long time. He came to the conclusion that most likely has to do with interference. Move your wiring and get some chokes. HTH.
Geez your refractometer sounds like a pain in the butt. I've got an el-cheapo one that I haven't calibrated in a year and a half. I don't bother with worrying about temp with it and it reads within .1-.2 of my classic glass hydrometer, a swing-arm hydrometer and my salinity probe.
Sounds like you are having a different problem with your probe, but to the people who have random spikes here and there, are you dosing anything by any chance? I don't notice it as much now that I'm just dosing vodka. I noticed it more back when I was dosing vinegar since I had to use 8 times as much. As far as I could tell, it would temporarily mess up the conductivity reading for a little while until the vinegar had time to fully disperse. Just a thought.
cha0s
New member
Trust your refractometer, not the salinity probe.
When I started up my first saltwater tank (about 3 years ago), I went through absolute hell to figure out my salinity. I was using the AC3 Pro w/ the Lab Conductivity probe and I couldn't get a consistant reading.
I took water samples to every LFS in town and oddly enough the variance in calibration of refractometers was significant. I got readings from 1.024 to 1.027.
I bought every brand of calibration solution available. I calibrated my refractometer with the pure water that came with it, RO/DI from my system and 35ppt solution. I calibrated my salinity probe with solutions from multiple manufacturers.
No matter how hard I tried, I could not get the salinity probe to agree with my refractometer, so I sent my refractometer back and had it replaced under warranty. I had exactly the same problem with the new one.
This time I took my refractometer to every LFS in town and compared my measurements of their tank water to my refractometer. I went to the best, most reliable LFS last and my calibration was dead on with their refractometer.
Considering this LFS is the source for most of my fish and coral, I accepted this reading as valid and have used it for the baseline ever since.
I never did get the salinity probe to agree with the refractometer.
Moral of the story - Use the salinity probe to detect change, not as the baseline. If you want, you can always calibrate it using your tank water as the baseline.
When I started up my first saltwater tank (about 3 years ago), I went through absolute hell to figure out my salinity. I was using the AC3 Pro w/ the Lab Conductivity probe and I couldn't get a consistant reading.
I took water samples to every LFS in town and oddly enough the variance in calibration of refractometers was significant. I got readings from 1.024 to 1.027.
I bought every brand of calibration solution available. I calibrated my refractometer with the pure water that came with it, RO/DI from my system and 35ppt solution. I calibrated my salinity probe with solutions from multiple manufacturers.
No matter how hard I tried, I could not get the salinity probe to agree with my refractometer, so I sent my refractometer back and had it replaced under warranty. I had exactly the same problem with the new one.
This time I took my refractometer to every LFS in town and compared my measurements of their tank water to my refractometer. I went to the best, most reliable LFS last and my calibration was dead on with their refractometer.
Considering this LFS is the source for most of my fish and coral, I accepted this reading as valid and have used it for the baseline ever since.
I never did get the salinity probe to agree with the refractometer.
Moral of the story - Use the salinity probe to detect change, not as the baseline. If you want, you can always calibrate it using your tank water as the baseline.
jmchzn123
New member
It's unreal to me that 500.00 worth of lab grade probes and controllers and it can't measure salinity. Frankly disgusted. An 89.00 refractometer is more accurate huh? I'm so annoyed. Should have used the AI controller and the refractometer and saved 400.00. It seems you went through the exact same thing I'm going through right now. Except I won't send the rmeter back now. There is exactly 2.1 difference in readings which is the 2.1 temp correction in the probe. But of course it should have nothing to do with it. I am going to try and calibrate probe w/o temp correction for kicks and see what happens. I'm obsessed with the 2 matching.... Lol
schwaggs
New member
The 2.1 is not an offset, rather a % adjustment as the PM2 temp probe measured temp raises or lowers from where it was when the probe was calibrated.
For what it is worth, my PM2 and Refractometer were right on to each other when I set them up. They are off from each other now but that is because I need to recalibrate the conductivity probe. I recently re-calibrated my refractometer and it was .002 off from when I calibrated it the last time so to say refractometers are somehow more reliable is also dangerous unless they are maintained on a regular basis as well.
For what it is worth, my PM2 and Refractometer were right on to each other when I set them up. They are off from each other now but that is because I need to recalibrate the conductivity probe. I recently re-calibrated my refractometer and it was .002 off from when I calibrated it the last time so to say refractometers are somehow more reliable is also dangerous unless they are maintained on a regular basis as well.
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sfboarders
New member
Mine was dead on with refractometer for months and then it spiked. I soaked it in vinegar for a few days and it was still reading high. I put some chokes and rerouted the wire on it and now the numbers are the same. I'm at the point now when I don't read the salinity anymore and decided to put it up for sale. It's only good to give a general area on where your salinity is. I trust my calibrated refractometer more.
I assume you're throwing out the $500 for dramatic effect. I'm also assuming you bought an Apex for more than JUST salinity measurement. Although between the PM2 and the probe it is over $200. So yeah it would be nice if it was more accurate, but that's just how those probes work. The conductivity probe I had for "that other controller" behaved the same, perhaps even a little worse. It's either that or no option for salinity whatsoever. It's the only technology available for Neptune to make a constant salinity measurement feature. Although mine behaves itself fairly well most of the time, so I'd like to think you can get yours working more reliably somehow.
And unfortunately I can't conceive of a way for an $89 refractometer to disable my ATO pump if the salinity drops too low.
