I found a internal parasite med at the last LFS wich had metronizole and sodium chloride. I put it into my tank an hour ago. It said to remove the active carbon, do a 25% change and then add 1 teaspoons for every 5 gallons. I should have just dumped the bottle into the tank insted of doing it a tsp @ a time. So I have to do a 25% every other day and add more med for upto 3 treatments