I read this in the link I posted to Amazon for fishben, and thought it was interesting: "Next method, the better of the two but you will need a syringe. I did a 25% water change before using this method. Take 100ml of aquarium water, dump in one full packet and stir. 1ml per 10 gallon, repeat every 12hrs till Hydra gone. This way you get more of a dissolved solution. One dose seemed to do it. In my tank I had various kinds of shrimp and babies, rabbit, mystery, mts, and nerite snails, dwarf crayfish, guppy, various live plants. All did well. If they return I still have my solution ready."