Eight filtration tests have been done at Hydro Aluminium’s reference centre at Sunndal. Two different grades of CFF (Ceramic Foam Filter) and two different grits of BPF (Bonded Particle Filter) from Pyrotek were tested. The alloy composition was the same for each test. The inclusion content in the melt was measured with LiMCA II and PoDFA upstream and downstream the filter. Selected filters have been cut and analysed with image analysis after use.