Salinity Dropping.

[SquidwardTentacles05]

My salinity has been dropping for nearly the past two months. My salinity was 35.6ppt (1.0267) on . About Two weeks after that, the salinity dropped to 34.8ppt(1.0261). Then at the end of January the salinity was 34.3ppt (1.0257). Then about a week ago, it was at 33.7ppt(1.0252). Today, it was only at 33.3ppt(1.0249). Why is it dropping?

 

[saltyfins]

Bump

 

[painter1982]

Do you do auto water change? That can do it if you take out more water than put in. Your ato will dilute. Salt creep can do it. Maybe your test method is off. Lots of reasons. You will need to give information about your system in order to understand why.

 

[Tahoe61]

What testing method, and replacement proceedure?

 

[slingfox]

What are you using to measure salinity?

 

[Randy Holmes-Farley Verified Community Expert]

Any removal of water that is replaced by ATO will lower salinity, such as wet skimming.

 

[SquidwardTentacles05]

What testing method, and replacement proceedure?

I use a calibrator.

 

[SquidwardTentacles05]

Any removal of water that is replaced by ATO will lower salinity, such as wet skimming.

My ATO always runs out of water.

 

[SquidwardTentacles05]

Do you do auto water change? That can do it if you take out more water than put in. Your ato will dilute. Salt creep can do it. Maybe your test method is off. Lots of reasons. You will need to give information about your system in order to understand why.

I use my ato for auto water changes, The salinity of the freshly mixed water is always at 34.5ppt.

 

[Randy Holmes-Farley Verified Community Expert]

My ATO always runs out of water.

Not seeing how that relates except you need to fill it more often.

 

[Randy Holmes-Farley Verified Community Expert]

I use my ato for auto water changes, The salinity of the freshly mixed water is always at 34.5ppt.

ATO means auto top off for evaporation.

How would you use it for water changes?

 

[Randy Holmes-Farley Verified Community Expert]

I use a calibrator.

You calibrate something with something???

What is calibrated with what?

 

[slingfox]

What testing method, and replacement proceedure?

I use a calibrator.

I assume you mean a refractometer? If you have one of those cheap ones from a local LFS or online vendor then it is likely not accurate. That does not necessarily explain the declining sanity though. To check how accurate your instrument is there is a thread on this board with instructions on how to make your own calibration fluid using table salt.

 

[SquidwardTentacles05]

I assume you mean a refractometer? If you have one of those cheap ones from a local LFS or online vendor then it is likely not accurate. That does not necessarily explain the declining sanity though. To check how accurate your instrument is there is a thread on this board with instructions on how to make your own calibration fluid using table salt.

No, I use a digital callibrator, I've been using it for 6 months now.

 

[slingfox]

I assume you mean a refractometer? If you have one of those cheap ones from a local LFS or online vendor then it is likely not accurate. That does not necessarily explain the declining sanity though. To check how accurate your instrument is there is a thread on this board with instructions on how to make your own calibration fluid using table salt.

No, I use a digital callibrator, I've been using it for 6 months now.

I haven’t heard about these before. What model specifically and have you compared it against a reference solution?

 

[Randy Holmes-Farley Verified Community Expert]

No, I use a digital callibrator, I've been using it for 6 months now.

I think you are using a nonstandard name for the device. Calibrator is something that calibrates, not something that measures salinity.

 

[Mandarinkeeper]

If practical, I would consider buying a Tropic Marin hydrometer. Dead on no calibration needed just measure the water at 77°. It is the gold standard to which everything else is adjusted and “calibrated” to

 

[Randy Holmes-Farley Verified Community Expert]

If practical, I would consider buying a Tropic Marin hydrometer. Dead on no calibration needed just measure the water at 77°. It is the gold standard to which everything else is adjusted and “calibrated” to

I understand your point and the idea that the TM hydrometer is a good way to go. I agree with that (assuming it is checked for accuracy at some point)

But drilling down, I think it's clearly not the gold standard. The modern seawater salinity scale is actually defined in terms of conductivity, not density (e.g., hydrometer readings). 35.000 ppt is seawater with a conductivity matching that of a solution containing 32.4356 grams of KCl in 1 kilogram of solution. That makes conductivity the gold standard method. :)

 

[Mandarinkeeper]

I understand your point and the idea that the TM hydrometer is a good way to go. I agree with that (assuming it is checked for accuracy at some point)

But drilling down, I think it's clearly not the gold standard. The modern seawater salinity scale is actually defined in terms of conductivity, not density (e.g., hydrometer readings). 35.000 ppt is seawater with a conductivity matching that of a solution containing 32.4356 grams of KCl in 1 kilogram of solution. That makes conductivity the gold standard method.