I've heard different things about hypo-salination and many conflicting opinions. All I can give you here is my experience and see if it's helpful at all. First, I would have to say that it may be necessary to use caution using hypo-salination in a quarantine tank as this process is somewhat stressfull and may be counter productive in a quarantine tank depending on how well the QT tank is done. On the other hand, I have used hypo-salination in a 75 Gal tank set up to be a reef. There were no corals yet kept in the tank, but had 1 cleaner shrimp, 50+ Misc. Hermits, 50+ Snails, 100lbs LR, 4"DSB, 5 Green Chromis, 2 Percula's, Royal Gramma, Neon Goby, and a Coral Beauty. When we first noticed the fish start scratching we ran a U.V. for 2 weeks, but were afraid to lose too many good critters from the DSB so we pulled it off. After finding the fish no better off the decicion to try hypo-salination was made despite the concerns of losing most of the rock and sand. Over the course of a week we dropped the S.G. down slowly from 1.025 to1.015. We kept it there for a month. To our surprize we didn't lose (as far as I could tell) one invert., fish, and the DSB continued to remain very active! The fish had no problems after that and the S.G. was brought back to normal. The tank continued on fine as though nothing was ever wrong and our biggest fear seemed tosomehow be avoided as there were still tons of pods, worms, mini brittle stars, and plenty of life on the LR as well! Believe me though, even with our success with this tank I would still consider this a risky way to treat a tank and it's no easy task either. The drop in S.G. as well as the return to normal must be very slow, the Temp. was brought up slowly also to 84 F. Calcium levels were kept to saturation and KH was kept a bit higher than usual at 14 dKH. So good luck with it and be carful, QT'ing is always best and low stress continues the responsibility of a healthy environment.
Later,
Myk.