Petmate Fresh Flow Erstatningskullfilter

Swapped in a fresh charcoal filter and within a day the water stopped smelling stale. I change it every few weeks now and the bowl stays clear instead of getting that slimy film. Cheap enough that I just keep a pack on hand.

My cat is picky about her water, but since I swapped in these charcoal filters, she's actually drinking more and the bowl doesn't get that slimy film as fast. They drop right into the lid and last a solid few weeks before I notice any change.

The water bowl stays noticeably fresher between cleanings, and the charcoal really does knock out that stale smell dogs leave behind. I just swap these in every few weeks and it's made a real difference in how often our pup actually drinks.