Aquatics - Aquarium Filtration - Revision Cards in Other Other

Mechanical Filtration Part 1

knowing the basics can help avoid filtration problems and understand how to deal with them when problems occur
mechanical fitration traps particles of uneaten food, fish waste, decayed plant materials and other aquarium debris
- mechanical filtration is the first stage of the filtration process
  - should always be placed so that this is where aquarium water hits first
- most mechanical media promote the colonisation of beneficial bacteria
  - particularly sponges or pads
- biological filtration is not the main function of this media
  - but cleaning and changing this media will impact the biological capacity of the filter
types of mechanical filtration media, which are dependent on the type of filter used
- some filters have pads, some have sponges, other have filter wool
- in some cases, mechanical filtration media is designed to hold chemical filtration media
  - e.g., cartridge media used in some power fibres
- materials have a range of coarse to fine, thus allowing for different degrees of filtration dependent on the pore size
- some filters have multiple layers of mechanical media, the coarsest being placed first to remove larger particles first

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Sponges, pads or foam blocks are used in canister filters and some power filters
- sold in rectangles, square or circles to match the opening of the filter basket
- some may have several pore sizes available which should be matched with the purpose for what they are used
- a very fine pore size may clog too quickly if used first in a filter
- there are filter sponges that fit to the powerhead or filter intake to reduce water flow as well as provide filtration
filter wool or floss is used in a variety of filters
- originated from tank box filters
- continues to be used in canister and wet/dry sump or trickle filters
- can be used when the carbon filter is removed, and stuffed in its place
combo cartridges are often used in power filters
- combines the mechanical and chemical filtration
- the exterior of the cartridge performs mechanical fitration
- the media provides chemical filtration
- carbon media should be discarded and replaced regularly

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biological filtration uses bacteria to remove potentially harmful substances from an aquarium
- when bacteria in the tank 'eat' any compound, including ammonia, nitrite and nitrate
converts one chemical substance into another
- ammonia to nitrite to nitrate
multiple types of bacteria are used in biological filtration
- nitrifying bacteria: remove ammonia and nitrite from the water
  - nitrosomonas: eat ammonia, convert it into nitrite
  - nitrospira or nitrobacter: eat nitrite, convert it into nitrate
  - grow best on filter media with a large surface area, e.g., bio balls, filter floss, sponges, ceramic noodles
- denitrifying bacteria: remove nitrates from the water
  - exist where there is no oxygen present
  - when there is oxygen the bacteria use this to breathe instead of the nitrates, which is a process that converts nitrates into nitrogen gas
  - occur in places such as inside rocks
  - volcanic rock and ceramic noodles are suitable media for denitrifying bacteria
  - for freshwater tanks denitrifying bacteria is the least important type of bacteria, most people skip over it completely

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remove chemicals from the aquarium
- including ammonia and nitrates
can also remove other pollutants such as: heavy metals, compounds (like sodium chloride), medication used to treat sick fish, tannins from driftwood that discolour the water
there are different types of chemical filtration
- activated carbon which removes chlorine and chloramine, dissolved proteins, water discolouration, bad smells
- zeolite is a natural volcanic rock that is made up mostly of silica and aluminium. It removes ammonia and is used in many freshwater aquariums.
- oxide (aluminium oxide and iron oxide) is just rusted metal and removes phosphates. Aluminium oxide can increase aluminium levels in a saltwater aquarium so saltwater aquarium owners should use ferrous oxide instead
- resin are used in water softening and purification. Man-made resins are made to remove specific chemical wastes such as phosphate and heavy metals.
chemical filters are not unlimited resources, and when they are full, they can start releasing chemicals back into the water and won't absorb any more
some chemical filters need changing every few weeks and others every few months

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