Copper is the gold standard for most ectoparasites, but especially crypt and amyloodinium.
You definitely do not want to use hypo/copper combo. Fish are continually drinking in saltwater to make freshwater for their metabolic uses when in NSW condx. As such they excrete the solutes thru their skin gills and kidneys. Telosts do not have the ability to concentrate their urine above what they maintain in their serum. With hypo condx, they do not need to process the water they drink in as much since it is close to what they maintain anyway. As a result they decrease their glomerular filtrate even less as there are less solutes to excrete.....all of this decrease in function is what allows them to have less metabolic stress and the ability to use more metabolic resources for immune function. Copper is hepatotoxic (liver) and largely excreted in urine. So, if less urine is produced, it will affect its normal clearance. Best to keep NSW condx as the copper will do all the work on the theronts anyway.