honestly where its just your refuge try placing an ad here to trade your liverock with someone for aiptasia free liverock i know theres always people looking for nudi food at an even trade. theres prob way too many and too small an area for manual removal and 5g isnt big enough for any fish that eat them. if you find someone to trade your liverock with drain your fuge or close it off from your display and scrape and thourly clean out your fuge to get rid of the rest.
unless you have fish that rely on the food your refuge grows then id say it might be a good time to start fresh with new rock and a clean fuge if it was a display id say fight it but since were only talking about a 5g refugium scrap it out and start fresh,aiptasia will find a way into your tank eventually.take the things youve learned from this refuge and apply them to the new cleaned one. be sure to unhook it from your display before doing any work so as not to upset anything or create any spikes of any kind.remember besides being a safe haven for pods and such your refuge should also help with nutrients not add to them so keeping it clean is a must to keep nitrates down and things like cyano from popping up
cheers