Question about SG

[lauraloulou]

Ok so the last time I brought my water to have it tested my SG was 1.024 and when I just tested it this morning it was between 1.022 and 1.023. The difference I am hoping is that my LFS lady uses a refractometer and I use a hydrometer. Is there any way that I can raise it back up? I planned on doing a 5gal water change tomorrow morning. Should I just add alittle more salt in the mix then normal? I just don't want to risk going too high!

 

[Randy Holmes-Farley]

In either case, I'd raise the salinity to more like sg = 1.026-1.027 by topping off for evaporation using salt water. That will raise it gently to NSW levels.

This has more:

The “How To” Guide to Reef Aquarium Chemistry for Beginners, Part 1: The Salt Water Itself
http://reefkeeping.com/issues/2007-03/rhf/index.php