Salt Treatment
Use non-iodized, mineral-free salt only.  Dosage is 3 lbs. of salt per 100 gallons of water.  Remove plants.  Over a period of 3 days add salt to the pond.  Add 1/3 dosage the 1st day, 1/3 dosage the 2nd day and then the last 1/3 dosage the 3rd day.  Leave in for 2 to 3 weeks.  After 2 to 3 weeks change 50% of the water. Then follow up with another 50% water change the following week.  Return plants to pond.  Find more information on Salt Treatments in our article, "Flash Dance - A Closer Look at Parasites".  Find Pond Doc's Pure Salt