Just thought that I would add the following link for another paper on this subject, that was published in the Canadian Veterinary Journal in 2015.
Treatment of diplomonad intestinal parasites with magnesium sulphate at a commercial rainbow trout (Oncorhynchus mykiss) facility
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4502860/
Treatment of diplomonad intestinal parasites with magnesium sulphate at a commercial rainbow trout (Oncorhynchus mykiss) facility
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4502860/