I drip water into my tank when the salinity gets out of whack and have never lost anything by doing this.
Today, I had to do it for my main tank. I just filled up a 5 gallon jug and stuck my tube into the bottom of the jug and tied it off to restrict the flow on the other side and had it drip into my tank.
The drip rate was about 1 drop per second.
My corals, fish and inverts seem to take the swings pretty well when I do salinity adjustments in this fashion.
Denise M.