Problems with tank

[j-bert]

I don’t see a reason to replace it with anything.

Okay cool! I appreciate that tip regarding the white media

 

[skidmarkstevie]

Ph?

Could be lower in your tank than their test do to ambient co2.

 

[Randy Holmes-Farley Verified Community Expert]

Specific gravity is relative density and has no units of measure. It is the density of the tank water divided by the density of pure fresh water at the same temp.

Density is mass per unit of volume, and has units such as grams per mL.

Salinity (ppt, parts per thousand) is essentially mass salt per
mass of total solution, though it is defined scientifically by conductivity (which becomes the salinity unit PSU ~ ppt)

 

[Peer.Boerner]

Okay then I’m confused because there is density, relative density, and salinity. What are the difference between these 3 because this is what kind of was throwing me off this AM. Both my glass hydrometer and refractometer both display my tank as fine. I think I’m confused about the 3 parameters as stated above.

I’m confused too. Curious what each one means.

 

[Randy Holmes-Farley Verified Community Expert]

I’m confused too. Curious what each one means.

If my explanation above does not clarify things, I'm happy to expand on it. :)

 

[Peer.Boerner]

If my explanation above does not clarify things, I'm happy to expand on it. :)

Sorry I should have been more clear. The ICP test show a density and relative density both of which are lower than @j-bert measured with his calibrated refractometer and hydrometer. I’m confused as to (1) what’s the difference in the ICP test’s density vs relative density salinity values, (2) why would they both vary significantly from those measured by J-Bert and (3) in this case, which salinity measurement should be authoritative?

 

[Randy Holmes-Farley Verified Community Expert]

Ignore density, unless you measure that, and just look at relative density (1.0248) which is a different name for specific gravity and almost exactly matches his refractometer reading of 1.025.

I don’t actually see a tank measurement with the hydrometer, just new salt water at 1.0255. That is close enough even if the tank is 1.0255, but it may not be.

 

[Peer.Boerner]

Ignore density, unless you measure that, and just look at relative density (1.0248) which is a different name for specific gravity and almost exactly matches his refractometer reading of 1.025.

I don’t actually see a tank measurement with the hydrometer, just new salt water at 1.0255. That is close enough even if the tank is 1.0255, but it may not be.

Many thanks Randy! Really appreciate you.

 

[Randy Holmes-Farley Verified Community Expert]

You’re welcome.

Happy Reefing!