Inclusions in aluminium is one of the most serious problems encountered in the production of aluminium ingots, and it can potentially have significant negative consequences for down-stream processing. In addition to gas purging, mechanical filters are one of the main ways to remove inclusions from the melt. Ceramic Foam Filters (CFFs) are commonly used to purify the metal directly before the casting process. The CFF is typically mounted in a filter box, and metal is passing through the box on its way through the launder. In the filter box, gravity is forcing the metal through the filter, and the metal keeps running through the filter on its way to the casting table. In standard operation, the direction of the metal flow is the same as the priming direction. In the present work, we have designed and built an equipment for testing the effect of reversing the direction of the metal flow through the filter after priming. Tests have been done where the interface between the metal and the filter have been studied, and the resulting filters have been examined metallographically.