joe's juice works pretty good when done right.
here are the steps:
- turn off the pumps and wait for the water to stop moving (turn off the lights too to prevent overheating of the water)
 
- completely cover the aiptasia in joe's juice (or clone product)
 
- wait 15-20 minutes, letting the little pile of joe's juice disintigrate the aiptasia
 
- suck up the joe's juice pile (along with the little aiptasia bits) with a syringe.  try to get everything
 
- turn pumps back on
 
- you'll probably never see it again
 
try to limit this method to 3-4 polyps every few days.  joe's juice (and simliar products) will increase your specific gravity (they're salt based).