A liquid filter arrangement including an internally received treatment agent storage and release cartridge is provided. The assembly is configured for diffusion of the treatment agent from the treatment agent storage and release cartridge, into liquid flowing through the filter arrangement. A particular arrangement shown is configured which provides for a dynamic type of liquid flow providing a current directed through the treatment agent storage and release cartridge. In the preferred arrangements, an initial static type of flow followed by later dynamic flow, is provided. Alternatives, methods of assembly and descriptions of use are provided.