My vet was very reluctant to prescribe Ivermectin for mites - said it wasn't really intended for them and because the mites don't live on the bird, you should treat the environment i.e. house. In this particular instance, I needed to make sure a broody was not eaten alive whilst brooding so I think he relented and it did seem to work. On the whole though you should try and clear the mites from the house, not treat the bird. I've never had much joy with diatom - it's supposed to break the reproductive cycle but I'm a little cynical. I've just ordered some of the natural predator (see other thread) in the hope that could be a miracle!