Thomas, my wife has this machine and I find that a simple flush with the Durgol Swiss Espresso Descaler works very well. What some people are seeing as a need for frequent back flushing is that the shower screen is getting dirty. On this machine, when you are finished brewing and steaming, you should just run the brew switch, without a portafilter in place, until it stops steaming and is just flushing water. This reduces the need to clean the screen. When the screen needs cleaning a short screwdriver with a #2 tip will easily remove the screen. Clean with a medium or soft brush and reinstall. Takes less than 5 minutes.