Which compressors are you using? The nebulizers aren't the issue, but from what I read on a post in the adults forum, different compressors vaporize the medicine in different size particles or something to that effect and with a lot of the cf drugs, you need the smaller particles that are only provided by a few compressors.
While the technical answer is of value, I'd also just like to know which compressors you have been using and if you have found they're effective in getting the drug administered?