Conductivity Meters: pinpoint vs used lab grade units
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Randy Holmes-Farley
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@Velcro I assume you're just using this to test NSW and the tank from time to time? I'm just curious why you made the jump to get it
I can't answer for him, but IMO, this device is perfect for acclimating fish because it reads both salinity and temperature constantly and in real time.
You can also measure limewater potency, which is somewhat tricky to do other ways.
And, of course, RO/DI function.
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Velcro
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@Velcro I assume you're just using this to test NSW and the tank from time to time? I'm just curious why you made the jump to get it
I'm just OCD and sick of trying to read my refractometer. This replaces my refractometer for making new saltwater. I will also use it for acclimation, RODI and kalk concentration, as randy mentioned.
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Velcro
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That meter looks slightly bigger. Maybe a benchtop type. The most important part is getting a probe that's in the right range of conductivity. I lucked out and mine is one of the really nice probes with a huge range. This PDF has a table towards the end that has the measurement range for each probe. You need one of the ones that includes 53mS/cm in it's range. Make sure you know there's a difference between mS/cm and µS/cm. 1000 µS/cm = 1mS/cm. I highlighted the ones that include what you need for saltwater below. These are the 2-electrode probes. Any of the 4 electrode probes on this PDF would work, so I didn't include a picture of them.
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Velcro
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Here's a meter just like mine which appears to include a probe that would be in a good range. If I'm reading the probe correctly in the ebay picture it's a 011510 which goes up to 200 mS/cm as seen on the above table.
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Velcro
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Velcro
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I had the milwaukee but to be honest it has pretty horrible accuracy at like +/- 0.002 SG if I remember correctly. I much prefer this over that for sure because of all the reasons randy stated (RODI conductivity, kalk conductivity).
Sorry...final question. The Pinpoint Salinity Monitor can be bought new for $100 with a 2 year warranty. What am I getting with the Orion model that I don't get with the Pinpoint besides the slower temperature compensation mentioned earlier?
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Velcro
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Good question. I can't find a spec sheet anywhere for the pinpoint so I have no idea what it's range or accuracy is. Keep in mind the thermo orion meters are lab grade instruments. I doubt the pinpoint uses a four electrode probe considering it's price, so that's a benefit if you are able to find one of these older orions with one. That prevents electrical interference from the tank (voltage leaks won't affect the meter).
@Randy Holmes-Farley Might have more insight on this.
Randy Holmes-Farley
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Both are perfectly adequate for seawater salinity in a reef tank.
The Orions have lower range and can measure RO/DI water. You need a different Pinpoint for that.
I'm not sure which Pinpoint can measure limewater (they seem to have removed the ranges from their site), but only 1 of them can.
I think the Pinpoint has 2 electrodes and the Orions typically 4. That cuts down on certain types of potential interference.
Randy Holmes-Farley
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In the many years I monitored it, the Orion 128 I had never drifted in calibration (and, in fact, could not be calibrated).
My commercial 30.1 mS/cm standard always read 29.8 mS/cm. year after year.
But I also never left it in the water 24/7. Just dipped it in when I wanted a measurement.
My commercial 30.1 mS/cm standard always read 29.8 mS/cm. year after year.
But I also never left it in the water 24/7. Just dipped it in when I wanted a measurement.
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Velcro
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Is the linearity pretty good on these things? I'd like to find an NIST traceable conductivity standard but doubt I'll find one that is 35 ppt.
Randy Holmes-Farley
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Yes, any corrections to conductivity should be linear.
reef_ranch
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Velcro, I bought the 105A+ you linked to. But I can't find a manual on line. Would you mind sending me the one you got by PM? Thanks in advance.
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Velcro
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Ab
absolutely!!!
