Types of Aquarium Filtration

With so many different saltwater aquarium filters to choose from, it can be really hard to choose the right one. And, if you are a beginner in the saltwater hobby it could be impossible. Saltwater fish and marine animals have completely different needs than freshwater fish when it comes to water quality. They are much more sensitive to water conditions and poor water quality can quickly lead to disaster. Understanding what each type of filter does can help you choose a saltwater filter that meets your needs.

Although the main function of an aquarium filter is to clean the water, filters also offer some other essential benefits. A filter keeps the water in the aquarium circulating. In their natural habitat, fish and marine life live among the swelling tides of the oceans currents. The filter helps keep the water in your tank from becoming stagnant. And, it also keeps a constant supply of air circulating through the water.

Mechanical Aquarium Filters

The mechanical filter is probably the most common type of aquarium filter. While it is an ideal choice for a freshwater tank, it’s not the best option for a saltwater tank. A mechanical filter simply filters out the waste and debris that is floating in the water. The water is strained through some type of filter medium such as paper, sponges, pads or floss. This type of filter will not remove any dissolved waste, algae or bacteria that can upset the stability of a saltwater environment.

Chemical Aquarium Filters

Chemical filtration systems generally use activated or regular charcoal to eliminate dissolved impurities from the aquarium. This type of filter will remove any toxins that are found in the water. But, it can also remove other unwanted chemicals such as heavy metals and chlorine. However, if you need to medicate your tank, you will need to remove the charcoal so that it doesn’t absorb the medication. Like wise, you can use the filter to remove any medication remaining in the water once the treatment is complete.

Biological Aquarium Filters

A biological aquarium filter is the most important method of filtration you can have in a saltwater tank. It is literally a living thing! Although the filter becomes a home for bacteria, it is good bacteria known as nitrifying bacteria. The bacteria takes in the unwanted substances found in the water. It produces its own waster products and creates the ideal setting for necessary bacteria to breed.

Toxic ammonia in the waste products are converted into nitrite and then converted into nitrate. Nitrate is less harmful than nitrite but it encourages the growth of algae. Once nitrite has been converted into nitrate, it can easily be removed during regular water changes or by using chemicals. The most popular type of biological aquarium filter is live rock. The rock is used inside the tank and colonized by beneficial bacteria that helps to filter the water.

Sump Aquarium Filters

New Aquarium - Sump Layout

 

The very best saltwater aquarium filtration system is a sump based system. However, it is also the most expensive because it requires additional equipment and plumbing. The sump itself is generally located underneath the tank in the cabinet, but can even be placed in another room, basement or closet. Water is diverted to the sump where it is filtered and then pumped back into the tank. This type of system usually includes a protein skimmer, filter sponge, substrate reactors and a filter sock.

Canister Aquarium Filters

Aquarium_Canister_Filter_UV_External_Filter_634546423318690630_1

 

Another really good choice for a saltwater aquarium is the canister filtration system. This multi-purpose filter can be used alone or in combination with other types of filtration equipment. Because it is the most powerful filtration system available, it is an excellent choice for anyone that has a lot of fish or marine life. The canister can be placed under the tank or inside the tank. The main disadvantage to this type of filter is that it has to be cleaned frequently.

Fluidized Bed Aquarium Filters

FluidizedBedFilterRLP1

Fluidized bed filters is a new concept that uses sand as the main filtration medium. The sand stays free of waste by an elevated water circulation. This is a simple filter that doesn’t inhibit the growth of beneficial bacteria. The filter has a submerged tube that is filled with sand through which water is pumped. The bacterial bed that is created in the sand does not even have to be disturbed during maintenance. While it takes longer for the filter to mature, it is very efficient.

Along with all of the benefits of a fluidized bed filter, there are also several disadvantages. The filter can become obstructed and reduce the levels of oxygen in the aquarium. And, while it doesn’t reduce the amount of CO2 and requires very little maintenance, it does not create enough oxygen in the tank. This type of filter is still very new and may not be the best choice for anyone just getting into the hobby.

If you have a really large tank, the filtration will be more efficient if you use two filters instead of one. The water will be cleaned and circulated twice as fast and all the strain of filtration isn’t placed on one filter. If the filters are placed at opposite ends of the tank, more of the debris will be able to reach the filter. And, as an added bonus you will always have a spare filter running just in case one of them fails.

Choosing what type of filter you want to purchase is just the first step in finding the right filter. You also need to decide what size filter you are going to need. The recommended tank size will be listed on the filters package and it is fairly accurate. But, this information is based on ideal tank conditions. If you accidentally over feed your fish, have too many fish or as the filter becomes clogged with debris, it won’t be as efficient in circulating the water. So, it’s generally recommended that you purchase the largest filter you can afford.