With copper based meds and hyposalinity, this kills off any beneficial bacteria that can be presented. Water changes are the only way to keep parameters in check.
This can be easily understood with the salinity. The bacteria that keep a freshwater tank aren't the same that keep a saltwater tank cycled. A salt system goes into the realm of brackish, not really the same circus anymore...just with less bears and more elephants.
Kinda like how trials are on a different map every week Mebbid.