If your tank have aptasia, my condolence to you. When I have aptsia, I can oly take the tank down and start over. After that said, I would not worry about it unless it is really near the mantel of the clam. Aptasia can sting the clam and especially can start growing right inside edge of the shell of the clam and give it lots of problem.
For me anything with aptasia will not go into my tank unless I can nuke the aptasia. If I see any aptasia on anything, the aptasia is dead, even if I have to tear the rock structure down to get to a tiny one.