Fish tanks need filters. They remove gunk from your fish tank as well as capture harmful chemicals like chlorine that you may have in your water. This is also where most of the aquarium water will flow to, taking any excess food and debris with it, allowing it to then clean the water before returning again safely back into your tank.

As fish swim in the water, they are constantly excreting waste. If this waste is left unattended, it will build up to toxic levels that can harm the fish itself. This is called ammonia stress and will make fish ill. Unattended food or decaying matter floating in the aquarium water can also contribute to cloudy water, but it is more commonly known as “not enough maintenance”. A dirty tank spreads germs and makes for a poor living environment for your fish, which leads to illness, stress, and premature death. So, Your fish tank must be a filter, whether it is a 10 gallon fish tank filter or 20 gallons.

How does a fish tank filter work

Filtration Methods

There are three methods of filtration; Biological, mechanical, and chemical. Biological filtration is absolutely vital in any aquarium because it helps reduce the need for water changes. Having a well-established biological filter enables pet owners to maintain high-quality water without having to change it too often. Chemical filtration can help remove impurities from large volumes of water, or it can be used to take care of problems with your source water or eliminate specific toxins that may otherwise harm living creatures housed within your aquarium system. It’s important to remember that you will want to make sure you have plenty of mechanical and chemical filtration in place if you live in an area where a lot of minerals are present in your source water.

Biological method

Biological filters include living organisms (bacteria and other microorganisms as well as plants and some fungi) that can be added to your aquarium, which will then help to convert toxic ammonia and nitrites into a less harmful chemical building block called nitrate. Your fish constantly excrete waste into the water of their tank, and if you do not clean this up, it will become toxic, affecting the health of your fish. Biological filters remove most of this waste to ensure that it does not change into nitrite, which is also poisonous to your fish.

If a tank is not cycled properly from the beginning, the buildup of toxic ammonia and nitrites can shut down their immune systems making fish susceptible to illness and disease. An accumulation of toxic ammonia and nitrites in pond water inhibits fish gills. The result is fish death due to suffocation. Nitrifying bacteria convert toxic organic waste materials into less harmful substances such as nitrate. Rapid bacterial growth, which can occur when biological filtration is not adequate contributes to high levels of algae growth in ponds.

Although aquariums require filtration, water clarity will be comparable to tap water prior to biological processes kicking in. Biologically active aquarium setups can have better overall water clarity than decorations, and bio-filters do not make any difference in terms of breathing requirements for either the fish or plants.

Mechanical Method

Mechanical filtration is a type of water filtration used in aquariums. It can be done with a few or many different materials. All of them are designed to improve the quality of water in your tank. The most common types include pushing water through activated carbon (also known as carbon filtration), gravel, and sponges.

The water quality in your aquarium will depend on several different factors. First, what kind of filtration media is being used? Fine-grade filtration media has smaller pores, which means that it can provide a cleaner aquarium that traps the tiniest of particles. However, if this grade of media is not kept constantly clean by either rinsing or replacing it, then you need to allowing more particles to enter your aquarium. Coarse-grade filtration media will allow larger particles to seep through but may take longer to become too full to continue working efficiently. An effective method when using multiple grades of filtration media is to start with a coarser one and then finish up with a fine one for optimal water cleaning.

Second, you should figure out how water flows from one end to the other. Is your passageway a straight shot, or does it loop around? The more twists there are, the longer it will take for the water to reach its final destination. And the less time water flows through your system before being cycled back, and the more time sediment can have to settle along its path before reaching where you want it to go.

Lastly, how often do you clean your filter? If you neglect to clean it regularly, then this will lead to poor water quality as the filters get blocked and compacted. An easy way to remember about cleaning the filter is either once every week or after two weeks, depends on how much water you use. Avoid letting your filter overflow, as this can be hazardous with the risk of mold growing inside your unit.

Chemical Filtration

Chemical filtration is often provided by carbon or chemical resins. These remove toxins from water, and it’s important to make sure that the resins are changed regularly so as not to end up with unsanitary water for your pet. Chlorine can build up on the resin over time, and that’s why you want to make sure and change it as often as necessary.

The activated carbon inside of Nature Spring water filtration systems typically provides chemical filtration over a 2-3 month period. However, it also depends on the following conditions:

1-Make sure you’re moving a lot of water through the carbon in your tank on a regular basis. Carbon is a great chemical-absorbing material that is supposed to remove chemicals from your water, but it will only work as well as it can if it’s moved frequently.

2- Water quickly saturates your carbon. Also, if you use too many nutrients that contain salt or other chemicals in conjunction with water changes, then this will accelerate the rate of saturation even further. Use only the necessary drops of fertilizer to get the desired effect on your plants, and plan out your water changes ahead of time by balancing them appropriately with flushes in between.

3-Switching up (swapping out) the water in your tank on a consistent basis prevents chemical buildup, increases oxygen flow, and saves energy since you won’t have to deal with the filter.


It is crucial to the health of your fish that you provide them with adequate filtration. The filter will help keep your tank looking nice, and there’ll be less stress regarding the upkeep, but excess rests on you in terms of making sure the tank is still functional, i.e., the necessary water changes, regular inspections for signs of abuse, stress, and diseases which can affect your fish.