I usually use Prazi or Formalin. Flubendazole is kind of an all in one treatment - flukes, nematodes, round worms, etc.. Also, it's very toxic so make sure you follow directions precisely! I recommend using a weight rather than a spoon but the directions should have come with the med. There are reported side effects with Flubendazole like tail standing, so again, follow the directions precisely! Flubendazole should be dissolved with a little vodka or acetone and mix thoroughly before pouring in the tank.
You should see positive results within a few days, but you must repeat the dose several times for a total of 21 days to fully eradicate the live flukes and their eggs.