If you've got no fish in, just add some saltwater with a lower SG
than you want. Depending on how much water you intend to change (of course, when you do your routine water changes AFTER your tank's cycled and you have fish in, you want to match up temperature, pH and SG
identically, or as near as physically possible, to your tank), just add less salt to the new water and get it to a lower SG
. If you want to fine-tune when the new water has mixed in your tank, either take out some water and replace it with fresh RO
water (if the SG
is still a bit too high), or take some out and put it in a container, and mix in some more salt (if the SG
is still too low), then put it back in. Don't add salt directly into the aquarium if you can avoid it.
You should be looking to get SG
in the 1.021 - 1.024 range, ideally.