# Filtration



## Chris S (Dec 19, 2007)

Last one until we can let these threads fill in a bit with information:

Proper filtration: How does it work, different types, the importance of it, recommended filters, size vs gallons, etc. etc. etc.

Post your experience and thoughts...


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## Darkblade48 (Jan 28, 2008)

*Types of Filtration*

*Types of Filtration
*
Filters are used in aquaria in order to perform several types of filtration: mechanical, biological and (sometimes) chemical.

In mechanical filtration, media is used primarily to trap dirt and/or other particulate matter that is produced in the aquarium. Mechanical filtration is important in order to keep the water column clear and free from particulate matter. It is important to remember that anything that is strained out by mechanical filtration only removes it from the tank; you will have to clean out your filter from time to time in order to remove the waste that has accumulated.

In biological filtration, various beneficial bacteria colonize (often specialized) media that you place in your filter. Such media includes special O-rings, sintered glass, bioballs, etc. These media promote the active colonization of the bacteria that will allow the nitrogen cycle to be carried out. The surface area of these media is very high, and very porous, providing the aerobic environment that the bacteria require for colonization.

Chemical filtration is the third type of filtration that a filter can provide. In this type of filtration, media such as activated charcoal or Seachem Purigen can be used. These types of media will help adsorb (not absorb) various dissolved organic compounds (DOCs) from the water column. For example, (new) driftwood often leaches tannins into the water; activated charcoal will adsorb these tannins and remove the tea-colour from the water. It is worth mentioning that in planted aquariums, usage of activated charcoal is not recommended as it will readily adsorb the chelated trace elements (but not the standard NPK fertilizers).


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## Darkblade48 (Jan 28, 2008)

*Types of Filters*

*Types of Filters*

Several filters exist on the market today in order to meet the filtration needs of various tanks. 
_
Sponge filters:_
The simplest of all the filters, these filters are powered by an airpump. These filters are often cheap, and are recommended for smaller tanks and/or fry grow out tanks, where little current is desired. The principle by which these filters work is that the air that is provided by the airpump will float to the top of the tube, creating a negative pressure that allows the water to filter through the sponge and subsequently exit through the tube.

_Undergravel Filter (UGF):_
Similar to sponge filters; the principal in which these filters operate is the same. Unlike sponge filters, the UGF is placed under the substrate (hence the name); as the airpump drives the filter, water is sucked through the substrate bed, in which the substrate acts as a mechanical filter. A distinct disadvantage of these types of filters is the fact that the substrate acts as a mechanical filter and can get clogged easily. This requires frequent gravel vacuuming in order to keep the filter in proper working order. In planted aquariums, UGFs are not recommended as plant roots will get tangled in them. In addition, some people argue that the extra flow of water pass the roots is undesirable for plants.

_Internal Filter_
Getting to slightly more advanced filters, these are AC power filters that sit inside your aquarium. They are often cheap, small, and have varying filtering capacities. They will often not have a lot of space for filter media, but can be used effectively in smaller aquariums.

_Hang on the Back (HOB) / Power Filter_
A slightly more complex filter is the power filter (or hang on the back (HOB) filter). The HOB filter is arguably one of the most common filters today (however, canister filters are also becoming very common and popular due to decreased costs, see below). The HOB filter, as the name implies, hangs on the back of your aquarium. These filters often have expanded capacity for media. Some power filters are slightly more advanced (such as the Marineland brand), with an included "bio-wheel" which allows for more surface area for beneficial bacteria to colonize.

_Canister Filter_
Finally, we arrive at canister filters, arguably the most efficient filters available today. Canister filters are often expensive, and many find this to be a disadvantage. However, canister filters boast the largest amount of media capacity, and can thus be cleaned less frequently (not never!). Some canister filters have media baskets which make rearranging the order of media much more hassle free. Canister filters work via a siphon principle: water is siphoned down into the bottom of the canister filter. The motorhead will pull the water up the canister, through the filter media, and back into the aquarium. Manufacturers such as Rena and Eheim make quality canister filters; these filters are the quietest of all.

Despite this seemingly endless variety of filters (some other types of filters not mentioned include wet/dry filters, fluidized bed filters, etc), it is important to remember that all filters do not permanently remove waste from your aquarium, it simply concentrates it into one location for eventual removal (by you!).


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## Darkblade48 (Jan 28, 2008)

*Filter Maintenance*

*Filter Maintenance
*
As mentioned already, filter maintenance is a proper part of keeping your aquarium healthy and clean, but also important for prolonging the working life of your filter. Several things are required in order to do this:

_Rinse the media (all filters)_
Internal filters/HOB filters: Weekly - biweekly
Canister filters: Monthly - every quarter (year)

Ideally, the media in filters should be cleaned on a regular basis. Filters do not permanently rid your aquarium of waste material. Instead, they concentrate it into one area so that you can remove it at a later time. Canister filters can have slightly longer periods between maintenance due to their larger media capacity. All filter media should not be rinsed under tap water; instead, some tank water should be withdrawn from the aquarium and the media rinsed and swished around gently in this water. This will prevent the beneficial bacteria that have accumulated from dying due to the chlorine that is present in tap water.

_Vacuum the Gravel (UGF)_

Only applicable to UGF, the substrate acts as a mechanical filter in this case. Depending on the stocking levels, the substrate may need to vacuumed frequently in order to remove the waste that has accumulated. This is so that proper filtration can still occur.

_Cleaning the motor head (canister filter) and impeller (all power filters)_

Motor head: monthly - bimonthly
Impeller: Bimonthly

The motor head of canister filters must also be cleaned every so often. This is not too difficult, for myself, this usually entails a quick wipe down whenever I clean my media. Impellers should be checked for damage, wear and tear, etc. Be very careful when cleaning the impeller, some are quite fragile, and the last thing you want is to have a broken impeller that needs to be replaced.
_
Lubricating the O-ring (canister filters)_

Canister filters maintain a water proof seal between the motor head and the canister filter via an O-ring. Ideally, this O-ring should be checked for cracks every so often (i.e. everytime you clean the motor head, or clean the media). This check is essential to ensure that the O-ring maintains a seal. In addition, lubrication of the O-ring with a silicon based lubricant (not Vaseline!) is important; this will help prolong the life of the O-ring. Ideally, this should be done every 6 months (though I must admit, I rarely do this).

The above times for filter maintenance are only meant as guidelines, they are what have worked for me. This does not say that you can go longer without cleaning your filter, etc (for example, the first time I cleaned my Eheim canister filter impeller was after 5 years of operation )


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## dekstr (Oct 23, 2007)

Great writing Anthony!

I'd just like to add that there are many different commercial chemical filter media for different purposes. For example, zeolite, phosphate removers, ammonia removers. There are also secondary filters like U.V. sterilizers, diatom filters, and wet/dry filters. Generally these are not neccesary for a successfuly aquarium, but would be nice to have if you have the money.

More filter media:

zeolite: Basically adsorbs ammonia and other nitrogenous compounds. 
It also takes in calcium extremely well--so it may be less effective in hard water. Good for additional removal of ammonia (i.e. when starting out) and to keep nutrients in the water column on down.

wet/dry filter / trickle filter: Aquarium water goes through a medium that allows for much more water/air exchange. As bacteria in the nitrogen cycle rely on oxygen to metabolize, the added oxygen in the air mixed with the water improves biological filtration ability. Although not very common, it is possible to use this for co2-injected planted tanks if you can seal off the filter to prevent too uch co2 loss. I think this is not recommended for reef set-ups as it encourages too efficient biological filtration. Nitrate is created too quickly with excellent biological filtration, which can build up very quickly. 

U.V. sterilizer: Aquarium water passes through a U.V. bulb in a closed container. The ultraviolet rays from the bulb kill all living organisms that passes through it. How this works is that the ultraviolet rays are mutagenic to bacteria and micro-organisms, destroying the molecular bonds in their DNA to render them harmless or from reproducing.

Diatom filter: Essentially this is a very powerful mechanical filter. Water is forced through a special powder of diatomaceous earth which is very fine (can go up to 1 micron in size), trapping all physical debris. This results in extremely clear water. The only downside is that the diatom filter is too efficient and clogs up very quickly. Some people use it permanently, whereas others use it only when guests are dropping by to impress them with crystal clear aquariums.


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## Darkblade48 (Jan 28, 2008)

Thanks, I try my best to do something productive when I'm slacking from my thesis writing 



dekstr said:


> ...whereas others use it only when guests are dropping by to impress them with crystal clear aquariums.


 I like this, it's very true!


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