Here’s a short article about cleaning/replacing your filter media: There are 5 main types of filters. I am only going to include filters that clean out stuff from your aquarium, not chemical, light(UV), specialty, in tank (who uses them anymore).. The filters job is to remove solid waste from your water. This can include food, fish poo, plant matter, and anything else that may happen to be in your tank. HOB (Hang On Back): This is one of the most common filters out there. It’s a box that sits on the back of your tank and holds your filter media. The filter media traps the garbage in your tank and keeps it there until you clean it out. These filters are great for beginners but for planted tanks they aren’t the best because they gas off Co2. Common brand names include: AquaClear and Marine Land’s Bio Wheel. Canisters: This is my favourte type of filter. It's basicaly the same as a HOB, but its not hanging onto the tank. Instead it’s underneath or to the side of the tank. A pipe sucks water in, it flows through some media (same idea as a HOB) and returns to the tank via a spray bar. A spray bar is a pipe with many holes drilled into it for the water to exit from. These are the best for planted tanks because most of the Co2 will stay dissolved in the water. Sumps: These are more common in salt water tanks. In the tank there’s a hole drilled, or a tank overflow that takes water out of the tank to a certian level and drains it to a glass or plastic box under the tank. There it flows through many chambers where media, bio media, chemicals, sand, etc are kept. In the last chamber is a pump that returns the water back into the tank. UGF (Under Gravel Filters): These filters go under the gravel (hence the name) and have two exit tubes on the ends. Water flows through the gravel and into the collection plate. It then goes into the uplift tubes where it is returned into the tank. The filter is powered either by an air pump or a power head. IMO these are the worst and are too “old school” when compared to the others listed above. If something breaks you have no choice but to destroy the whole tank because it’s under the gravel. If not cleaned properly they can become nitrate factories. A better choice would be RUGJ or Reverse Under Gravel Jets. Sponge Filters: These filters are really basic. It’s a sponge, a stand, and an uplift tube. Normally powered by an air pump or a power head. Water comes in through the sponge and out the uplift tube. These are great for fry tanks as there are no moving parts, and they can not get sucked into them. Cleaning a filter: With any filter cleaning is basically the same because they all use the same media. Cleaning a filter is very important for its proper function. Sponges: These are super easy to clean. Once every 2 weeks you can take them out and swish them around in some old tank water or some water that has no chlorine in it. Reason being chlorine will kill the bacteria in it. They only need to be replaced when they are falling part. I have had mine for over a year. Carbon: Carbon is not needed in a normal tank. Carbon takes out meds, color, and odor. None of which should be present in your tank always (except if you have driftwood). It will become un active in about 2 weeks. After that it is useless and will not be doing anything. Bio Media: Bio media is any media that is designed to house bacteria. They can be ceramic noodles, Bio Max, plastic Bio Balls. They only need to be cleaned in old tank water every few months. As long as they are not clogged it should be fine. Choosing and maintaining your filter will make fish keeping much easier. Filters are a must. It’s the life support for your fish. Without it, everything may die because nothing is cleaning out the gunk that’s in your tank. There are some filters less tanks that use plants as a natural filter. This gives a nice effect but is not the easiest thing to do. Good luck with your fish keeping!