Information provided by TetraPond
Filtration preserves the aquatic life in your pond by removing impurities and it is important to keep it running at peak efficiency. Depending on your type of filtration system, clean and/or back-flush on a regular basis (or when you observe a reduced water flow) during the summer months to maintain good water quality.
Gently rinse any biological media in a bucket of pond water. Depending on your type of filter, the biological media can be anything from plastic cylinders/spheres to spaghetti-like strands. Biological media should never be washed under the hose because the chlorine found in tap water kills the beneficial bacteria.
Also, remember never to scrub the media clean. Simply rinsing off any excess sludge or debris with pond water will allow beneficial bacteria to remain intact and active, therefore restarting the biological process. Avoid spraying the foam pads with a hose since they provide surface area for beneficial bacteria as well; instead, use pond water to rinse the foam.
Remove and clean the foam pre-filters on submersible pumps or the debris basket on external pumps to maximize their performance, allowing them to circulate water to the filter efficiently.