The Beginners Guide to Aquarium Filters

When you first begin your aquarium hobby, it can be considered a milestone passed when you learn and understand how your aquarium filter works. This essential piece of equipment for your aquarium is certainly a must-have, but beyond this many people don’t understand exactly how the filter works or why it is so important. To help you understand the full ins and outs of your aquarium filter, we have put together a beginner’s guide which will help you gain an understanding of what your filter is doing and why it is essential. Plus, you can find the answer to all of the questions you might not have known you had!

Plus, don’t forget to explore our wide collection of aquarium filters online now to find the best option for your tank today.

Do Fish Tanks Need a Filter?

The most obvious question that might have prompted you to understand more about aquarium filters, is whether they are actually important. Do fish tanks need a filter?

The simple answer is, yes. An aquarium filter will help you to maintain a safe and healthy aquarium environment for your fish that allows them to thrive. The filter works to keep your aquarium water clean by filtering out debris and toxins, such as ammonia and nitrites. As well as this, aquarium filters can help to oxygenate the water and provide a place for beneficial bacteria to grow.

But understanding the why and how are often two entirely different things, so to help you gain a better understanding of this process it can be useful to break down aquarium filters for beginners. 

How Aquarium Filters work for Beginners

To best understand how an aquarium filter works, let’s break it down into stages.

Mechanical Filtration

The initial stage of aquarium filtration can be referred to as mechanical filtration. This refers to any part of the filtration process that uses a physical barrier to remove solid debris from the water. Mechanical filtration usually involves a form of sieve, sponge, foam or matting to capture the solid matter, such as fish waste and surplus food that would otherwise contribute to turning your water murky.

However, it is important to note that mechanical filtration does not act to break down any solid debris. So instead, it requires a lot of maintenance to keep it in full-functioning order. You can do this by regularly cleaning the foam or matting in the filter in aquarium water and then simply squeezing out the dirty water into a bucket.

You should also make sure to replace the media in your mechanical filtration periodically, and you can find the perfect replacement for your filter in our wide range of filter media available at Pond Planet.

Biological Filtration

The second stage in the filtration process is biological filtration, this is a little bit more advanced and is a process that occurs naturally to an extent. Meaning that without a full filter system, your tank will still experience some biological filtration but not enough for your fish to survive.

A majority of aquarium filters feature chambers that contain biological filter media, and this often takes the form of ceramic media which has a high surface area to volume ratio. Water flows throughout the porous sub-structure during which it comes into contact with nitrifying bacteria colonised on the high surface area of the bio-media. This process filters the dangerous chemicals in your aquarium water into less harmful Nitrate, which can be removed via regular water changes.

For example, the fish in your tank will produce waste in the form of Ammonia. This is a dangerous chemical in the water, but as the Ammonia laden water passes through the filter it will come into contact with nitrifying bacteria, which turns the Ammonia into Nitrites and then finally Nitrates.

When it comes to fish keeping, this is one of the most important parts, as without an adequate amount of beneficial bacteria in your filtration you can incur dangerous amounts of Ammonia in the water. High Ammonia levels will lead to poor fish health as can inhibit their breathing, burn their scales and potentially lead to fish fatalities.

Top Tip!

While incredibly important, biological filtration can take some time to establish itself in a new fish tank and therefore be effective. For this reason, we advise using a filter start treatment as well as fishless cycling, to begin with!

Aquarium Filter FAQs

How Long should the Aquarium Filter be On?

In your aquarium, your filters, heater, and air pumps need to stay on always to keep your fish alive. However, your filter especially needs to stay on 24/7, and should not be turned off unless it is for cleaning purposes and cleaning should only take an hour or two to complete.

How Do I Know If My Aquarium Filter is Working?

A quick and easy way to determine if your filter is still fully functioning is to check water is still flowing from the filter outlet. If the flow rate is dramatically reduced or there is no flow at all, then it may be time to repair or replace the water filter.

Why Does My Aquarium Filter Get Dirty so Fast?

Even with a functioning aquarium filter, you may notice your tank gets dirty quite fast and your filter is struggling to keep up. If this is the case and you are regularly cleaning your filter, there may be a couple of other issues that you might want to consider. The following problems may be the source of your tank being exceedingly dirty despite a filter, so consider whether there is too much food, exposure to sunlight, a lack of live plants, or too many fish in your tank.

Can You Over Filter a Tank?

It is not possible to ‘over filter’ a tank, only to under filter it. This is why it is important to have an aquarium filter, as well as keeping it on and running at all times as previously mentioned. This ensures a healthy balance of good bacteria is present in your aquarium.