I understand your frustration. I fought these things for over 6 months with a couple of my fish. But even every three days is too much. The eggs do not hatch all in the same day or at the same time so at any given point a fluke egg will have hatched, the oncomiridium will begin its search for a host and it will attach itself to the host. This can happen within a matter of hours but it takes at least two more weeks for this fluke to grow up old enough to reproduce. In the meantime of course many other flukes have hatched and begun their life cycle. If you dip once a week you will get all of those that have hatched. In other words you can do a dip and kill five flukes, dip in another three days and kill five more, dip in another three days and kill five more or do just one dip in 10 days and kill 15. Easier on the fish, easier on you with the same results.