I have the same model, mine started leaving dirty marks and not draining properly. I took it in garden emptied all water from bottom under filter. Removed filter then u need to undo star shaped screws to get at impela. I found a small rubber band, garlic bulbs, mushroom slice etc. Clean out as much as you can.Then re-connect and tip in aenough clean water to base so as not coming out of door. Run full cycle with tablet/rinseaid and wow clean again!! Worked for me anyhow..
Alan, August 2005