[amcarrig]

Sounds more like brown jelly disease than RTN. What I would do if the coral was mine (and this is only my recommendation for LPS corals that have brown jelly disease):

(1) Move the coral to a seperate vessel for treatment and gently rinse the brown jelly off with tank water. (2) 30-60 second fresh water dip. This might stress the coral so keep an eye on it (3) 30 minute Lugols dip (10 drops of Lugols per gallon of tank water) (4) Place it back in the tank where there is good flow across the coral.

RTN is not something you can "remove" from a tank. You have to remove the cause of the event and since rtn can be caused by several variables, you'd have to figure out which one made it happen (overheating, too much light, dirty water, etc.).