Plant scale filtration experiments of 10``×10``×2``, 30PPi Al2O3 and SiC industrial filters were carried out. Wetting experiments show that the SiC filter wets better with molten aluminium than Al2O3. The assessments by LiMCA II and laser were employed to study the behaviour of the two filters. The Al2O3 filter shows improved time dependent behaviour, increasing filtration efficiency, during one hour filtration. This is not the case for the SiC filter. It decays faster than the Al2O3 one. The SiC filter requires less pressure drop to infiltrate the metal. The result suggests that the SiC can be a new filter choice in the aluminium industry.