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Filtration and their careAquarium Accessories

The heart and sole of any aquarium is its filtration system.  It is here that the waste that can kill our fish is collected, and turned into relatively harmless compounds. You probably get your car serviced regularly, but how often do you service your filter. In this article we will look at the different types of filters available and servicing and maintaining your filter. 

There are five primary types of filter configurations: Undergravel, wet-dry, hang-on-the-back, canister and the box. The undergravel filter has limitations, but remains a reliable and simple design. The box filter is inefficient, since water can easily by-pass the filter media. The hang-on-the-back filter is an excellent mechanical filter, but the canister filter is the most efficient chemical filter, and overall, is probably the best design. The wet-dry filter is basically a gas exchange filter that provides direct loss of ammonia to the air as well as excelent conditions for biological filtration.

There are three types of filtration: mechanical, biological and chemical:

  • Mechanical filtration is merely the removal of insoluble particulates from the water by some type of sieving device, such as floss or foam.
  • Biological filtration is the removal of ammonia and nitrite waste from water by Nitrosomonas and Nitrobacter bacteria, respectively, and is the most essential of all filtration types. The most reliable aerobic biological filter is the wet-dry. Anaerobic biological filtration converts nitrate to nitrogen. Equipment has also been designed for algae scrubbing where nitrate and orgnic waste is removed by algae culture.
  • Chemical filtration is the direct removal of solutes by adsorption. The most important function of chemical filtration is the removal of nitrogenous organic waste. this is vital, because such waste is both inhibitory to the biological filter and increases the load on the biological filter.

The most familiar chemical adsorbent is activated carbon. Activated carbon should be a litter larger than a pinhead in size. When washed and dry, it should be dull and not shiny. When placed in water, it should hiss. It should also tend to float at first. Other types of chemical filtration include synthetic adsorbents, ion exchangers and zeolite. Zeolites are white, dusty clays, usually sold for removing ammonia from freshwater. Zeolites are ineffective for removing nitrates.

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Regardless of the type of filter you are using or its efficiency to clean the water in your aquarium, the following is a typical cleaning reigime for each type of filter:

Undergravel FilterUnder Gravel Filter

  • Use a gravel cleaner to remove sludge and excess detris from the gravel at least every 4 weeks
  • Add a bacteria booster every week or as directed to break down waste and feed bacteria colonies in the gravel
  • Replace the airstones in the uplift tube every 6 months
  • Ensure the air pump maintains good air flow, and check diaphrams in the air pump when pressure reduses
  • If ndergravel filter has carbon cartridges, replace them every 2 months

 Box Filter

Box Filter

  • Place activated carbon in the bottom 1/3 of the filter and replace every 2 weeks
  • Place filter wool in top 2/3 of the box and replace weekly
  • Ensure the air pump maintains good airflow, and check diaphrams in the air pump when pressure reduces

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Overflow Filter

  • Rinse cartridge under tap water every week and replace every 2 months or sooner if clogged
  • If filter has biological media rinse monthly under tank water and replace only if media deteriorates
  • Clean impellor and well with a bottle brush to remove sludge and slime


Canister Filter

  • Rinse biological media under tank water (saving a bucket of water from the tank when water changing is ideal to rinse this media)
  • Rinse out all mechanical sponges. These should normally be replaced every 6 - 9 months
  • Rinse chemical media and recharge per instructions. If carbon is used replace every 2 months
  • Change filter wool with every clean
  • Clean impellor and well with bottle brush to remove sludge and slime
  • Clean inlet / outlet tubes with pipe cleaner every 6 months


Wet / Dry Mini ReefMini Reef

  • Replace pre-filter wool weekly
  • Clean impellor and well from return pump with a bottle brush to remove sludge and slime


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