Chemical Filtration in Aquariums

Chemical Filtration and saltwater aquariums

Hey Salt-Nation, Jeff Hesketh here, with another great article for saltwater aquarium hobbyist on chemical filtration and how it applies to keeping a saltwater aquarium. If you’re new to saltwater aquariums or, looking to start on I strongly recommend starting with my Start Here page. Now lets jump into everything you need to know about Chemical filtration.

To keep your aquarium inhabitants disease free, a healthy aquarium environment is essential for all fish keepers. In the aquarium, successfully maintaining aquatic inhabitants is dependent on the proper installation and maintenance of a complete water filtration system.

To maintain good water quality and sustain the life of the aquatic inhabitants, filtration system is very important. Filtration is a method or technique for isolating an insoluble solid from a liquid. There are three types of filtration system.

The three types of aquarium filtration are:

  1. Mechanical filtration
  2. Biological filtration
  3. Chemical filtration

These filtration systems must be present and it should be worked properly to maintain the water quality and sustain the life in a freshwater or marine aquatic environment. In this case, routine maintenance is necessary to keep these filter systems working properly.

What is Chemical Filtration

Chemical filtration is the process or method by which dissolved organic compounds or potentially dangerous pollutants are removed from the freshwater and saltwater systems. Chemical filtration also removes other waste materials such as nitrogen through chemical reactions. Filters are essential for the health of your aquarium. It keeps the nitrogen cycle going and help keep your tank inhabitants healthy.
Filter media are anything which is placed in a filter that changes the quality of water flowing through it. To create the optimum environment in your aquarium, you should choose the suitable type filter media among the variety of media.

There are many filter media in different forms. Among them some can use in the chemical filtration system. Some of these chemicals include: carbon, zeolite, phosphates (phosban, phosguard, phosphate pad) or heavy metals (Seachem’s copper removing resin), peat moss, calcium hydroxide, poly adsorption pads and other chemically treated media.

There are also many other additives and vitamins to aid in supplementing the efficacy of the chemical filtration. Chemical filter media maintains high water quality for an extended period of time. Chemical filtration media also needs to be changed periodically, otherwise it becomes full of toxins and can’t hold any more pollutants.

Chemical Filtration Media

Activated carbon

Activated carbon

The most common type of chemical filtration media is granulated, activated carbon. Carbon is generally activated with a positive charge and is designed to attract negatively charged water contaminants. It is also known as activated charcoal. There are many different brands of activated carbon on the market. Activated carbon is relatively cheap and can easily be purchased. It helps to remove a variety of pollutants such as chlorine, chloramines, dissolved proteins, medications and other organic and inorganic compounds. They are not effective at removing minerals, salts

and dissolved inorganic compounds. It also removes odors and discoloration to create crystal clear aquarium water. Oxygen depletion is caused by the use of too much carbon. You can avoid this by presoaking the carbon for an hour before placing it in the aquarium filter. It is a safe practice to run the activated carbon in your filter for several weeks to ensure that any contaminants that may have been on the aquarium glass, decorations or substrate are removed from the water column.



It is microporous, aluminosilicate minerals. It is commonly used as adsorbents.  It can adsorb ammonia, nitrate or phosphate from the water. These media are generally referred to as ion exchange media which can removes unwanted or harmful substances from the water by exchanging them with a harmless chemical.  Zeolite is unaffected by antibiotics and other strong medications that can harm filter bacteria. Zeolite works very well in tanks where stocking density is low. There are many forms of zeolite which can rapidly reduce large concentrations of ammonia from the water column. Some forms can also be soaked in saltwater to recharge their absorptive abilities for reuse within your aquarium filter. It is available in both natural and synthetic forms. Zeolite filtration is used in marine tanks to keep nutrient concentrations low for the benefit of corals adapted to nutrient-depleted waters.




There are two types of media that apply ion exchange principles. These are man-made and natural resins. Man-made resins and natural resins attract contaminating pollutants and exchange those compounds with beneficial compounds. Ion exchange resins work great in combination with activated carbon.  Resins attract and remove specific water toxins via ion exchange. Within this process, resins draw charged toxins, such as ammonia, from the water column and exchange them with less harmful compounds, such as sodium.

The greatest advantage of most resins is that it works to neutralize a variety of aquarium pollutants.  These work by attracting a specific molecule to adhere to them. Some attract ammonia or nitrate, and some remove dissolved organics. Ion exchange resins are also utilized in some carbon mixtures like Chemi-Pure and Bio Chem Zorb. The resins often strengthen the filtering ability of the carbon, as well as help biological activity by removing pollutants before they enter the nitrogen cycle.

This type of chemical filter media absorbs phosphates and other pollutants from your water. High Phosphate levels are a contributor to algae growth. If your aquarium has a very bad algae problem, phosphate-controlling media could be used along with regular water changes to help control this problem. It is formulated for use in both freshwater and saltwater aquariums and it does not affect pH. It is a standard all-purpose filtration media that also contains ammonia binding properties. It also helps to remove both phosphates and silicates

Foam Fractionization

It is also referred to as protein foam skimming.  Usually, this filter system is  tall and columnar in shape.  The principle is to pump water and tiny air bubbles into the column.  This air or water contact time allows the toxins to bind to the tiny air bubble and form a scummy foam.  This foam contains many bad elements from the aquarium water.  It is a also considered an auxiliary filtration device. It is primarily used in saltwater applications and good for toxin removal.

Utilizing a protein skimmer can reduce the need for water changes, increase the levels of dissolved oxygen in the water and help support proper PH levels.

Chemical Filtration Media Video


Chemical Filtration Conclusion

The filtration system is responsible for keeping the water clear and free of toxic substances that are dangerous to the inhabitants. To ensure the health and vitality of your aquarium inhabitants, you should maintain  good water quality through proper aquarium water filters. In addition to proper lighting, substrates, shelter and food, it is important that your tanks are equipped with sufficient fish tank filters.

Without a proper filtration system, the ammonia and other wastes are produced by your fish or other aquarium inhabitants and it becomes toxic and even poisonous. To preserve the beauty of your tank and promote the health and happiness of your fish today, you should use the best fish tank filters with suitable filter media for your saltwater aquarium.

For more in formation on Chemical Filtration check out this article.


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