Aquarium filters are an everyday fact of life for the aquarium experts at FSA&L. Aquarium filtration is a very broad subject because of the many approaches to filtration and the many different schools of thought. The approach to filtering aquariums has changed over the history of aquarium keeping and all approaches have their upsides as well as their downsides in regards to effectiveness and ease of maintenance. In respect to the broad range of filtration methods and systems this FAQ will deal with the most popular and typical types of filters that are available to the general aquarium hobbyist and aquarium fish enthusiast. The aquarium filter categories we’ll discuss will be canister filters, hang-on-back filters, wet/dry filters, and undergravel filters. Canister filters typically sit below the aquarium; they are an enclosed filter with no exposure to open air, usually comprised of (2) parts; the head piece which contains the motor, and the body piece which houses the filter media. The (2) pieces are clamped together with a water tight gasket seal. Canister filters are pressurized filters meaning they have a pumping mechanism which forces the aquarium water through the filter by way of (2) lines or hoses, an intake and an output line, drawing water from the aquarium and returning the filtered water to the aquarium. Canister filters allow for mechanical, biological, and chemical filtration and should be cleaned about every 8 weeks for good maintenance practice. Many people believe these filters only need to be cleaned once very 6 months; this would be poor maintenance practice. Canister filters can be used for both freshwater aquarium and marine aquarium. The aquarium professionals at FSA&L recommend using canister filtration for fish tanks of 90 gallons to 250 gallons, or as supplemental filters for larger systems. Hang-On-Back Filters attach, or hang, on the backside of the aquarium. These are great filters for the smaller aquariums ranging from 10 to 90 gallons and can even supplement larger aquariums. These are motorized filters that have an intake tube in the aquarium which draws water up into the filter; the water passes through carbon filled filter cartridges which perform mechanical and chemical filtration, and then returns the water to the aquarium by way of a spillway. These are uncomplicated, easy to maintain filters that require monthly cleaning consisting of changing cartridges and rinsing the filter unit. Hang-on-back filters are great for providing aeration and circulation for the aquarium environment. The aquarium maintenance professionals at FSA&L recommend hang-on-back filters for freshwater use only. Wet/Dry filters sit below the aquarium, have a rectangular box shape, and are relatively large filters that are excellent for both freshwater and marine aquariums. Wet/Dry filters are usually used for aquariums from 90 gallons to aquarium systems upwards of several thousand gallons. Wet/dry filters offer mechanical, biological, and chemical filtration. Water coming from the aquarium enters into the top of the wet/dry filter and passes through a mesh type of material to remove debris from the water, then the water is passed over a “drip plate” which spreads the stream of water of a larger area allowing it to drip over a column of biomedia which is exposed to open air creating an oxygen rich environment which is very effective at breaking down organics (or nutrients) in the water. After passing through the biomedia the water flows into a basin (or sump) then through a polishing sponge to remove very fine particles and is pumped back to the tank; filtered and free of debris and sediment. Chemical filtration on the wet/dry filter system usually takes place after the water has passed through the polishing sponge. Wet/dry filters are easy to maintain and require monthly maintenance, sometimes more, of the sponges; and at least an annual cleaning of the biomedia for a properly maintained filter. The aquarium service techs at FSA&L recommend wet/dry filters for larger aquariums, marine systems, or tanks that house large fish. Undergravel filters are housed in the aquarium. The “UG” filter is a flat slotted plastic plate which sits on the bottom of the aquarium and is installed before the gravel is put into the tank on top of the plate, hence undergravel filter. A 1.5”-2” bed of gravel is most effective for this type of filtration. The UG filter is a biological filter with a marginal degree of mechanical filtration ability. These filters are run by air pumps or powerhead pumps. The undergravel filter draws water down through the gravel, under the plate, and then passes the water back into the water column at the top of the tank through lift tubes. These filters can be used for freshwater or marine aquariums and are highly effective biological filters. To maintain the undergravel filter the aquarium substrate needs to be siphoned monthly, there is no need to remove the UG filter for monthly maintenance; however, once every few years it is beneficial to clean under the filter plate. These filters cannot be used with sand or substrate that has a measurement of smaller than 3mm grains. Undergravel filters although often by-passed by today’s hobbyists are extremely effective and have been credited with making the ease and popularity of the aquarium hobby what it is today. The aquarium experts at FSA&L recommend undergravel filters for all types and sizes of fish tanks. To discuss any of the numerous other approaches to aquarium or pond filtration contact the New Jersey aquarium experts at FULL SERVICE AQUATICS or call us at (908) 277-6000 for complete information, watch for future FAQs on this subject matter, or schedule a one on one aquarium consultation service with one of our NJ aquarium services professionals.