dang I do 1/2 interceptor and half a fluke tab. I just leave them in there for a long time, as they've shown that it's more effective to treat over a longer period of time than it is to use a ridiculously high dose (neither the interceptor nor the fluke tab have ever shown negative side effects at 1000x or more the dosage originally recommended).
I do the same thing that mike does, but I only use half a crushed fluke tab.
I've gotten redbugs though :/ Hopefully that's it, and since then I've treated my whole system a number of times, and have not seen any since.