We use Prohibit Levamisole Hydrochloride Soluble Drench Powder Anthelmintic by AgriLabs. We sometimes use Fritz Expel-P.

STEP 1: Clean the aquarium.

STEP 2: Remove all carbon and UV sterilizers. 

STEP 3: Do this step at night with the aquarium lights turned off. Dose 0.01 grams of Levamisole hydrochloride per gallon of water. For example, we would dose a 75-gallon aquarium with 0.75 grams of Levamisole hydrochloride. (75 x 0.01 = 0.75) We use a 0.001g digital scale (Like this one on Amazon) Note: if using Fritz Expel-P, you dose one packet per 10 gallons of water.  

STEP 4: Wait 24 hours. Then do a 25% water change while cleaning the bottom of the aquarium. You can add back any carbon or UV sterilizers.

STEP 5: Repeat treatment weekly for four to six weeks.