Please Help Diagnose

[KoolAid28]

My clown was fine last week. The clown is a false perc. He started breathing heavy and not eating about 4 days ago. He slowly started being less active and started hiding last morning. Now I came in to see how he was doing and he seems to be worse. He is pale and still beathing heavy. I do not see any spots or redness around his gills. The mouth area seems very pale color of white. He is not scratching surfaces either. I do not see excess slime either. The fins seem fine, and eyes are not cloudy. I really need help diagnosing to know how to treat. I am fixing to do a freshwater dip. Readings are fine. temp 79, ph 8.1, ammonia 0, nitrite 0, and nitrate 0, sg 1.023. He is now in a QT.

When I perform a FW dip, how to I raise the FW to 8.2? Do I use a buffer?
Do I add some tank water to raise the SG to 1.010?

I purchased the clown 3 weeks ago. There has not been any other fish.

I perform 5% water changes every 3 days with aerated RO/DI and IO.

I feed frozen krill, brine, mysis, and omega one flake.

[ReefGeekster]

Here's a link that may help until someone professional can answer your questions.

http://www.wetwebmedia.com/dips_baths.htm