Jungle's instructions ......
For internal parasites, give 3 doses, leaving 48 hours between doses, and make a partial water change before each new dose. Keep activated carbon out of the filter until 48 hours after the 3rd dose has been added. After the 3rd dose, wait a week before determining whether another 3-dose regimen is necessary.
For external parasites, give three doses, leaving 6 days between doses, and make a partial water change before each new dose. Keep activated carbon out of the filter for at least 24 hours after each dose.