Specific gravity & saliniti questions

[weblance]

I just got my new digital temperature/saliniti/specific gravity meter today.

It measures the temp. to 25.7 degrees celsius, normal. The specific gravity was measures to 1.022 and saliniti was measured to 30 ppt.

The question is: what is the difference between saliniti and specific gravity? Are my readings normal, if not what do I do to correct them?

Thanx

/Carl

 

[Mariner]

Your numbers are a little low if you are keeping corals and inverts, although fish will do well at those levels. Most reefers keep their tanks between 1.025 and 1.027.
I'm no scientist, so this is a layman's explanation: Salinity measures how much salt is in the water. Specific gravity measures how dense something is compared to pure water. Since the density (SG) of saltwater increases as you add salt (increase salinity), there is a direct correspondence between the two measurements.
The best way to increase SG/salinity is just by evaporation. As H20 evaporates and the salt doesn't, your SG/salinity will increase gradually. When it gets to the point you want it, add fresh top off water occasionally to keep it there, and make water changes only with water of that particular SG/salinity.
HTH,
Mariner