Salinity

[reefandfish85]

Not sure if this is right forum, but feel free to move it if not.

So I was using refractometer which was calibrated at first at everything was fine. Then I noticed that some of my corals were not fully opening and some sps started browning and STN. I checked by water and everything was fine.

Alk 8.6
CA: 445
MG: 1230 little low but OK
PO4: 0.23
NO3: 5
PH: 8-8.3
Salinity 1.026

Unfortunately by refractometer was off and when re-calibrated it was showing 1.022 , since then I had raised my salinity back to 1.026.

But questions remains how to really tell what measuring device to use. My Refractometer is calibrated with Pinpoint solution and well as my Pinpoint Salinity Monitor which both showing about same now. I recently got Hanna Salinity checker which calibrated to Hanna solution at 35ppt but showing my tank at 1.024. Is this just their accuracy error or is pinpoint wrong ?

Which one to trust more ? Is the calibration solution correct ? or Just pick one and go with ?

I would rather stay within 1.025 - 1.026

 

[vetteguy53081]

Not sure if this is right forum, but feel free to move it if not.

So I was using refractometer which was calibrated at first at everything was fine. Then I noticed that some of my corals were not fully opening and some sps started browning and STN. I checked by water and everything was fine.

Alk 8.6
CA: 445
MG: 1230 little low but OK
PO4: 0.23
NO3: 5
PH: 8-8.3
Salinity 1.026

Unfortunately by refractometer was off and when re-calibrated it was showing 1.022 , since then I had raised my salinity back to 1.026.

But questions remains how to really tell what measuring device to use. My Refractometer is calibrated with Pinpoint solution and well as my Pinpoint Salinity Monitor which both showing about same now. I recently got Hanna Salinity checker which calibrated to Hanna solution at 35ppt but showing my tank at 1.024. Is this just their accuracy error or is pinpoint wrong ?

Which one to trust more ? Is the calibration solution correct ? or Just pick one and go with ?

I would rather stay within 1.025 - 1.026

Quickest and easiest way to tell is to take some water to a trusted LFS and have them test for you and see what they come up with

 

[reefandfish85]

well I kind of did that as friend of mine is doing maintenance service and he tried his and it ended up at 1.025 so now got three different tester and three different reading pretty much 0.001 away from each other.

 

[Randy Holmes-Farley]

Quickest and easiest way to tell is to take some water to a trusted LFS and have them test for you and see what they come up with

You would assume the LFS is accurate?

 

[T-J]

Pick one and stick with it.

 

[MnFish1]

Not sure if this is right forum, but feel free to move it if not.

So I was using refractometer which was calibrated at first at everything was fine. Then I noticed that some of my corals were not fully opening and some sps started browning and STN. I checked by water and everything was fine.

Alk 8.6
CA: 445
MG: 1230 little low but OK
PO4: 0.23
NO3: 5
PH: 8-8.3
Salinity 1.026

Unfortunately by refractometer was off and when re-calibrated it was showing 1.022 , since then I had raised my salinity back to 1.026.

But questions remains how to really tell what measuring device to use. My Refractometer is calibrated with Pinpoint solution and well as my Pinpoint Salinity Monitor which both showing about same now. I recently got Hanna Salinity checker which calibrated to Hanna solution at 35ppt but showing my tank at 1.024. Is this just their accuracy error or is pinpoint wrong ?

Which one to trust more ? Is the calibration solution correct ? or Just pick one and go with ?

I would rather stay within 1.025 - 1.026

Usually 1.025-26. You shouldn't really calibrate a refractometer with another device (i.e. how do you know which is right - the pinpoint or the refractometer. Instead you buy refractometer calibration solution - which is a salinity of 35 - and use that to calibrate your refractometer. Some people use RODI - that is also not appropriate.

PS - it would surprise me if the coral issues were caused by a SG of 1.022 - even if that was 'correct'

 

[reefandfish85]

Usually 1.025-26. You shouldn't really calibrate a refractometer with another device (i.e. how do you know which is right - the pinpoint or the refractometer. Instead you buy refractometer calibration solution - with is a salinity of 35 - and use that to calibrate your refractometer. Some people use RODI - that is also not appropriate.

I did not calibrate refractometer with another device I used the same solution

 

[Randy Holmes-Farley]

Not sure if this is right forum, but feel free to move it if not.

So I was using refractometer which was calibrated at first at everything was fine. Then I noticed that some of my corals were not fully opening and some sps started browning and STN. I checked by water and everything was fine.

Alk 8.6
CA: 445
MG: 1230 little low but OK
PO4: 0.23
NO3: 5
PH: 8-8.3
Salinity 1.026

Unfortunately by refractometer was off and when re-calibrated it was showing 1.022 , since then I had raised my salinity back to 1.026.

But questions remains how to really tell what measuring device to use. My Refractometer is calibrated with Pinpoint solution and well as my Pinpoint Salinity Monitor which both showing about same now. I recently got Hanna Salinity checker which calibrated to Hanna solution at 35ppt but showing my tank at 1.024. Is this just their accuracy error or is pinpoint wrong ?

Which one to trust more ? Is the calibration solution correct ? or Just pick one and go with ?

I would rather stay within 1.025 - 1.026

The Pinpoint fluid should be suitable for calibration or checking all of these devices.

If you calibrate them and then measure the Pinpoint fluid, they all read the same? but then in the tank they read differently?

 

[ApoIsland]

This is all I have used for 11 years:



They are so cheap Maybe pick one up just for a backup to be able to quickly double check.

 

[vetteguy53081]

You would assume the LFS is accurate?

Yes- but then again they’ve been known to sell bad RODI water and saltwater that had very low salinity
Reason I say Trusted LFS- one you hope you can count on

 

[reefandfish85]

The Pinpoint fluid should be suitable for calibration or checking all of these devices.

If you calibrate them and then measure the Pinpoint fluid, they all read the same? but then in the tank they read differently?

When I calibrate with same solution refractometer reads 1.026, pinpoint is at 53mS ( 1.026) but Hanna is at 33ppt ( 1.0245) - tank water

but they read the pinpoint fluid correctly all of them

 

[Randy Holmes-Farley]

When I calibrate with same solution refractometer reads 1.026, pinpoint is at 53mS ( 1.026) but Hanna is at 33ppt ( 1.0245)

What measures 33 ppt? The calibration fluid? You want to check each device in the calibraiton fluid.

leave tank measurements out of the picture for now.

 

[reefandfish85]

How did you calibrate the Hanna? It should read 35 ppt

I read your question wrong hanna shows 34.9 in calibration solution

 

[MnFish1]

I did not calibrate refractometer with another device I used the same solution

OK - your wording is a little confusing. But your question was how do you decide which device to use right? My point was use any self-calibrated device. The way I read what you wrote is - I had coral problems, I measured by SG it was 1.026. But when re-calibrated it showed 1.022 - and you then increased your salinity back to 1.026. In a later post you said you calibrated it using 'pinpoint' - so that can mean a couple things - you used a Pinpoint device, or pinpoint solution.

so - I'm assuming you used pinpoint solution.

No you raised your salinity back to 1.026 - but there is still a disparity - now a Hanna checker is reading 'low' but the refractometer is 1.026. Again - apologies if I'm ins-stating what you did - but thats the impression.

My answer would be - use the refractometer - calibrate it with Salinity 35 solution - often - and stick with those results.

BTW - curious - about the corals - how did you increase your salinity (how quickly)

 

[reefandfish85]

BTW - curious - about the corals - how did you increase your salinity (how quickly)

Over 3 weeks with higher salinity (1.030) water changes (10%) and topping of with salt water instead RODI

I did not loose anything but one hammer is still not fully opening but mu NY Knicks and other one were not affected by salinity issues.

 

[Randy Holmes-Farley]

I read your question wrong hanna shows 34.9 in calibration solution

OK, so all devices read ~35 ppt (~53 mS/cm) in the same Pinpoint calibration fluid.

But then they read differently in the aquarium?

 

[reefandfish85]

OK, so all devices read ~35 ppt (~53 mS/cm) in the same Pinpoint calibration fluid.

But then they read differently in the aquarium?

correct

 

[Randy Holmes-Farley]

correct

OK, and in the tank you get what values after proper calibration of reach device?

Each of them is making temperature corrections, and one or more may not be doing it correctly.

 

[reefandfish85]

OK, and in the tank you get what values after proper calibration?

All right well I just went and recalibrated everything again as I did this few days back and they seems to read about the same now..

Pinpoint: 51.4mS ( 33.7ppt)
Hanna : 33.3 ppt
refractometer: ~33.2ppt (harder to read but its between 33 and 34)

Odd when it was incorrect before, maybe I just need to get calibration solution by the gallon

 

[Randy Holmes-Farley]

OK, glad it is all worked out now.

+/- 1 ppt is about the limit of accuracy of many of the devices we use.