I have a fluval fx5 and a 404 now i need to clean the foam in it so do i drain the canister and then just wash out the foam, Or get entirely new foam??
Use a bucket full of tank water to rinse the "gunk" outta the filter pads. You could rinse them out in the sink but you'd kill off some of your bacteria colony. If you replace the pads with new ones, you're removing that bacteria colony entirely. When the filter pads on my 404's get nastier than nasty (usually about 6-8 months), I only replace two at a time.