I have had a major outbreak in two smaller tanks (20 L and 40 Cube) - Aiptasia X only made them multiply. I added a file fish to the 20 Long first but he went after acans so he was banished to the 40 cube. In went the Berghias. It took some time but the nudis cleaned the 20 L and I have never had an aiptasia come back. Now I kind of ignored the file fish for some time as my cube was so over run with aiptasia that it was being neglected. The front glass was covered in film algae and one day I cleaned the glass and every single aiptasia was gone. The file fish got every single last one. There were hundreds if not 1,000.