So treating Popeye in betta that is otherwise healthy. Used kanaplex for several doses not much improvement changed them to seachem metroplex and seeing vast improvement. This with keeping water clean changed every few days is resolving his issue. It takes time to heal Popeye. The metroplex seems to be doing the job. I used a little api salt on one water cha ge but but I don't use it regularly. If you don't see improvement by third dose of whatever you are using, it's probably not the right treatment. Just sharing what worked in my situation.