wait 100% water changes? check ur ph. I had a massive die off because of a ph swing. What filtration are you using?
you should probably take care of the planaria...
By 100% water changes she means that she's only used RO water for the tank. She only changes 10% ever two weeks.
Sorry to hear about your ongoing loss. I'm simply regurgitating what people have said but I agree on checking parameters and slightly lowering temp just to be on the safe side