Can't stop the losses

[Aquattro]

The first thing that I read here is that you've done a lot to try and stop it. Maybe too much change too quickly?
I suffered the same type of losses a few years back, due to what I believe was vibrio. I treated with an antibiotic and losses did stop. For me though, it was fairly simple to tell, since anytime I scratched my arm working in the tank, I'd get a nasty infection.