The Science Behind Filtration: There are two forms of filtration that are critical to maintaining a successful ecosystem pond: mechanical and biological. Through mechanical and biological filtration, the water garden will process a variety of nutrients found in the system, including fish waste, uneaten fish food, leaves, and runoff from lawns. How to Choose the Right Filter for Your Pond. Choosing the right filter for your pond or water garden can be an intimidating and daunting task, so let us break up the task into easy-to-digest categories and desired functionality. There are advantages to every type of filter, so we will list the features and benefits of each option, making it simple and easy to select the correct filter for your application. NEW PONDS The advantage of choosing the right filter before you get started should not be underestimated. Aquascape takes an ecosystem approach to water gardening. This approach uses a skimmer and BioFalls®. The skimmer removes leaves and debris from the surface of the pond, optimizing water quality. A BioFalls® Filter performs two very important functions: it supports mechanical and biological filtration and provides a great start to any waterfall. EXISTING PONDS In some circumstances it is difficult to add a skimmer and BioFalls® to an existing system. Perhaps the shape or building technique makes it prohibitive. In this situation we recommend the use of an UltraKlean™ Pond Filter, Submersible Pond Filter, Pond Waterfall Filter, or Pond Filter Urn. These filters will retrofit quickly into existing systems and provide efficient mechanical and biolocial filtration.