never known of any problems with proflavin use.if you want acriflavine powder to get appropriate dosage strength i can give a contact who will supply direct.At 5 grams per ton coupled wth half ounce salt per gallon will kill all protozans in one pass and does not affect filtration.The one drawback is colour of pond during treatment,what do you want crystal clear crap water or healthy fish.

regards chris m.

koimasters