When I did tank maintenance for large displays, we used to make a "salt slurry" that would have a concentrated mixture of salt that we would pour in while the hose ran fresh water into the display. You have to really mix the salt slurry up good and distribute it slowly but it work for the huge, fish only tanks(300-1000G). I would not recommend doing that with a reef. The salt could harm anything it lands on when it isn't dissolved.