Clamlvr, I have not used Stop Parasite so i cannot comment on its effectiveness, but I can tell you that clams are sensitive to foriegn chemicals and compounds in the water. Looking at your tank, with all the SPS and clams, I would leave it alone. If you can catch some of your fish, quarantine them and go the hyposalinity route.
While your fish are in quarantine, you can also nuke the parasite with whatever you choose. Ich is not harmful to corals or clams - if anything it provides food for them while in its larval free-swimming phase.
The cost of your fish is trivial compared to your SPS and clams. Be patient and wait it out. The longer you wait, the safer it will be. Ich cannot survive without a host.