The filter needs to be cleaned every 6 months. When cleaning your filter only switch the sponge/cotton substance and do not rinse out or improve any of one other media from the filter. In the event you are currently a PADI Accredited diver, you are able to dive into this https://garretteijjk.jts-blog.com/35996139/the-single-best-strategy-to-use-for-aquarium-cleaning