Salinity levels - 1.025 or 35ppt?

[fishgate]

1.025 or 35ppt? I see both of these #s thrown out often. 35ppt translates to around 1.026. Does it make that much of a difference? I keep it at exactly 1.025 at 79 degrees.

[tidus10]

I use 35ppt cause its an easier number to see on my refractometer.. but honestly IMO there is NOO difference between 1.025 and 1.026 and 1.027.. its all pretty dang close..

[tmz]

Actually: 1.026 is 35ppt ;1.0252 is 34 ppt; 1.0268 is 36ppt. Personally, I target 1.026 as 1.0264 is the average natural seawater value. A conductivity meter or digital refractometer can give you digital readouts that are easier on the eyes.

[noj3333]

If I had the ability I would love to keep my water at 1.0264, but with my refractometer I used 35 ppm, it's just easier for me to be more accurate, and maintain stability.

[pyithar]

i try to keep mine at 1.026 but i don't think .001 difference will have any significant effects on fish and corals. the main thing is to keep it stable.

[tmz]

35ppt is a fine target it's 1.026.

[droog]

When reading salinity in PPT using a digitial refractometer is the value temperature sensitive or not?

-droog

[delor-02]

i try to keep mine at 1.026 but i don't think .001 difference will have any significant effects on fish and corals. the main thing is to keep it stable.

+1

Stability is the key. When I rescued my current tank, it was about 1.035! It got that way slowly and had been constant. The fish we alive (wouldn't say thriving). I had to bring it down slowly to not shock anything.

[delor-02]

When reading salinity in PPT using a digitial refractometer is the value temperature sensitive or not?

-droog

Most refracometers I have seen are self adjusting for temperature (at least they claim to be).

[droog]

Most refracometers I have seen are self adjusting for temperature (at least they claim to be).

Yeah, I read somewhere that SG readings needed temp adjustment wheres readings in PPT do not. So I was largely ignoring temperature.

Now I think about it this doesn't really make sense. I assume the device does only one thing (measure diffraction) but presents the same reading in different formats (S.G / PSU / PPT). So water temperature probably does matter, even if reading in PPT.

The water at my mixing station is much colder than tank water (10 C vs 25 C) so the difference in reading between can be quite significant. Not sure if the device measures ambient temperature or that of the sample. Temp readout seems pretty inaccurate and slow to change. Is there an optimal way to use these devices to get best measurement regardless of temperature?

-droog