Review on Enhance Filtration Efficiency with Marineland Bonded Filter Sleeve for Magnum 350 Canister Filter by Kristi Wood

I bought a Magnum 350 almost for nothing at a garage sale, I needed filters to make it work, the only ones available seem to be those from the pump manufacturer. I wish they were cheaper, especially when buying charcoal. But I should note that I am using a pump and these filters on a freshwater setting; I don't know if it's my tank setup or this filter but Marineland's instructions say you don't need to replace these filters unless they are once a month, in my experience they will within a few weeks dirty and if you leave it for a month (you never have to wait a month to change the filter) it will stop the flow of the pump.