When you visit for example a Koi show, you always see a high variety in filter systems: sieves, drum filters, trickling filters, chamber filters, bakki showers, moving bed filters, bead filters, you name it. They all have the same purpose, and that is filtering the water. But what exactly is filtering and why is it so important to filter your water? What kind of filter is neccesary for my pond? Well, it is not that difficult to find out, but unfortunately widely unknown….