+1...are they the only fish in the tank? Or only fish 'showing' ick? (so far)There is no way to successfully eradicate Ich without removing the fish. You can "manage" the problem via nutrition, but it will never completely go away.
Two clowns shouldn't be that hard to catch; have you tried a fish trap?
Hypo in a reef tank???The only other way is hypo salinity for 8 weeks or more.
IS it a reef tank?
The OP doesn't appear to have said it's a reef tank. If it's fish only then hypo in the display might be an option.
He called it a reef tank in the thread title
I have had success with a vortex xl diatom filter, on two seperate occasions over a three year span. Both times was after I introduced a new fish with out having a qt and both times the powder brown tang was the first to show signs of ich. I started running the diatom 24/7 for four weeks and never had a breakout on my other tangs. And this is on a 300 gallon fowlr. I can also say that it's not a fix all and the best practice is to go fallow and qt every time, I eventually lost my entire tank to velvet. Good luck.