Your filter is at the heart of a clean aquarium. Without great filtration your fish will become unhealthy, get sick with disease and most likely die. The filters prime objective is to filter the water through a series of steps. Its job is to convert any waste in the aquarium back into fresh useable water fish like. This is achieved with bacteria which live in the filter media. This bacteria breaks down ammonia(fish urine and other waste) & nitrite converting it into nitrate that is less harmful to your fish. Nitrate levels will begin to rise over time and to reduce this a water change is necessary. Every 1 – 4 weeks is recommended. Plants will help to use up any leftover fish waste or fertilizers that are in the aquarium but they can only absorb so much. Once levels get above a certain point it is best to do a water change. Nitrate at 40-50ppm is the most you should push it with your fish so you do not stress them out . Usually if you do a 50% water change then you will drop your nitrates by 50%. With day to day living and how busy it can get, some of us would want to do this at different times. All tank setups are different.

Filtration will depend on;

  • How many fish you have
  • What lighting you use & number of hours
  • What type of filter you own
  • Quality of Filtration Media

How many fish you have:

The more fish you have in the aquarium, the more waste is produced by them. Your filter can only breakdown a certain level of waste. There are additives you can use to help minimize this like Carbon, Ammonia, Nitrate & Phosphate Removers.

What lighting you use and the number of hours:

What lighting you use will determine the amount of water changes needed and the frequency of these changes. The stronger the light, the larger or more frequent a change is needed. The lights will be responsible for the amount of Algae that will build up in the tank. If you own an aquarium, then you will experience a build up of algae in it. Frequent water changes will help to keep levels down. Algae itself in smaller doses won’t hurt your fish but it can get out of control very quickly and this will smother the oxygen in the water. Imagine walking around in a house with little oxygen, you wouldn’t have the strength to do very much. This will also lower their immune system.

The number of hours your lights should be on will vary. This should be between 8 – 14 hours a day. Depending on the type lights you have. To keep it simple, algae will be determined by the amount of light hours ,intensity of that light & how much fertilizer used. The quicker algae builds up in the aquarium is an indication that you have to reduce your light hours, fertilizers or do more water changes. No sunlight should touch a tank at any time. This will result in a massive algae bloom.

What type of Filter you own:

Good filtration starts with a good filter. There are so many different types of filters on the market it’s hard to know which one to choose. Canister, Internal, Hang-on-back or Under gravel filters. These are the four main categories of filters. Each has their good points. It’s up to you to decide which one you want to use. Getting one the right size for your aquarium is a great start. This should be determined by the size of your tank and how many fish you are wanting to keep. With an excessive amount of fish it is best to get one bigger than suitable for the size of your tank. Two filters would be even better. The setup of filtration media in the filter will differ from person to person.

It is best to use 3 stages of filtration media. These are;

  • Mechanical
  • Chemical
  • Biological


This is the first stage of filtration and best to use something that will trap large particles of debris from your aquarium. Filter wool or Filter foam works extremely well. These two products will help the second and third stage of filtration. You can also use carbon to break down waste particles.


This is the second stage of filtration and will also aid the latter. This is where any additives should be placed for modifying the water chemically. Ammonia Remover, Peat Moss, Zeo-Carb, Crushed Coral Etc. These will need to be added periodically and taken out when they have passed their usefulness. At this stage it is also a great idea to add some Bio Media. This will start the process of bacteria breakdown that will help in the third stage.


This is the last stage of your filtration before water will flow back into the aquarium. This water has been cleared of debris and is the cleanest, allowing bacteria to thrive. You want to give the bacteria the best possible change to break down ammonia & nitrite. The media placed into this area should be bio rings or any other material to help bacteria to flourish.

Always make sure there is a constant flow of water for good filtration. Not having any flow will be uncomfortable for your fish. Fish are quite sensitive so any vibration will be felt, even from other fish in the same tank. No circulation leads to poor health and stressful environment. A constant water flow will eliminate this. The fins of your fish are quite delicate, too much water flow for certain species may damage them. You can always apply a reducer on the end of your out pipe to slow down the amount of water flowing out of your filter. Some filters have adjustments on them that will do this for you.

Quality of Filtration Media:

All Filtration Media will help your aquarium but how good that help is, will depend on the quality of the media itself. With so many brands flooding the market, it can be sometimes hard to know if they are good or not. Just because a company says their brand is the best, doesn’t mean it is. The best advice to give you would be go by recommendations of a product from a blog, forum, review or word of mouth. This is a quick and easy way to get the exact product you need. Although sometimes the best information you ever get is through your own trial & error and personal experience.


Bear in mind the information provided is a general overview of basic filtration and health of your fish. Any extra information you may need, feel free to contact us at Serene Aquarium as we look forward to hearing from you, whether query, feedback or to share your own personal experience.