How do I carry out Hyposalinity Treatment?
It can seem daunting, but it's relatively simple if you've got the right equipment. Your initial goal is to get down to SG 1.009 over the course of about 36 hours. This needs to happen slowly to avoid osmotic shock, but needs to happen before the fish succumbs to the parasite. Doing water changes with RO water is the fastest and safest way to do this, but you need to monitor the specific gravity along the way. Start with a 15% or 20% water change. This should bring your SG down from about 1.025 to roughly 1.020. Do it again 12, 24, and 36 hours later, with the fourth water change bringing the SG to roughly 1.010. After you get here, it's best to give it several hours before making the final adjustments to 1.009. There...you did it. You're treating with Hyposalinity.
Now that you're there, keep an eye on your pH. Hyposalinity can have ill effects on pH and you should check it at least once a day and adjust as necessary. Also, be sure to top off evaporation regularly to keep your SG stable at 1.009. You'll need to keep it at 1.009 for four to six weeks, or at LEAST four weeks after the last signs of the parasite. In addition, your display tank needs to be fallow (no fish in it...inverts are fine, but NO VERTEBRATES.) for at least 30 days to ensure that there are no parasites left in any of the various stages of its life cycle around to cause problems once the fish go back in the tank.
At the end of treatment, raise your specific gravity back up to natural levels SLOWLY! Bring it up over the course of several days. My preferred method is to top off evaporation with natural strength saltwater, as well as performing water changes with it. As you get closer to the desired point, you'll need to use hypersaline water for the last little boost up to natural SG (1.025-1.027, with 1.0264 being ideal).
All that's left to do is transfer your fish back to the display tank! Congratulations! Be sure to acclimate them to your tank, as conditions are different and you don't want to shock your fish with any of your parameters after all this hard work! Hopefully now you'll quarantine any new arrivals and reduce the risks of future outbreaks.
Links:The thread on ReefCentral.com where I got a lot of help when my own fish were sick:http://www.reefcentral.com/forums/showthread.php?s=&threadid=1093252A great resource, also where I got a lot of information for this post:http://www.petsforum.com/personal/trevor-jones/marineich.htmlhttp://www.petsforum.com/personal/trevor-jones/hyposalinity.html