Mechanical and biological filtrations are both important for maintaining a healthy aquarium.
While you might manage without chemical filtration, you really can’t overlook the importance of mechanical and biological filtration—they work hand in hand.
Even though biological filtration plays a key role, skipping mechanical filtration could lead to poor water quality.
Below, I’ll explain what mechanical filtration is and why it’s so essential for your tank.
I’ll break down how it works and share some interesting facts that highlight its significance.
What exactly is mechanical filtration?
Mechanical filtration is nothing more than one of three types of filtration that you can use in your fish tank.
I already mentioned the other two at the beginning – biological and chemical filtration.
Mechanical filtration can be explained in a very simple way.
It works similarly to a fish net. Water can flow freely through the net but the fish are trapped inside.
In mechanical filtration, water flows through dense materials like sponges or filter wool (also known as filter floss).
These materials trap waste such as fish poops, uneaten food, dust, dead plants, and other particles, keeping them out of your tank water.
Mechanical filtration keeps the water clear and prevents debris and other particles from circulating back into the tank.
This filtration method is essential for any aquarium and needs to be running all the time, 24/7.
Why? Without it, all that gunk we just talked about would circulate back into your tank, making it dirty and unhealthy for your fish.
Now, maintaining your filter media is crucial. If the trapped waste starts to decompose, it could increase nitrite levels in the water, which isn’t good for your fish.
Plus, a clogged filter means less efficient filtration, as water flow through the media decreases.
The fix? Regular cleaning and replacing of the filter media.
When it comes to cleaning your aquarium’s filter sponges, it’s best to rinse them in the dirty water you just remove from your tank during water changes.
That’s right — use the old “dirty” tank water.
Filter wool or floss, you can rinse it the same way, but it’s often easier to just remove it out for a fresh one.
Remember, never clean mechanical filter media under tap water as it could kill the beneficial bacteria crucial for biological filtration.
Without these bacteria, your tank could see a spike in harmful ammonia or nitrite levels, which can be dangerous for your fish.
What are the different types of mechanical filtration?
Generally mechanical filter media are classified according to the size of the pores, holes through which water flows.
Pore size varies with the coarseness of the filter: coarser media have larger pores, while finer media have smaller pores.
If a coarser filter medium allows some waste to pass through, it will be caught by a filter with finer pores.
You might wonder why not use the finest filter from the start to catch everything?
This is a very good question buy the reason is simple and practical.
Very fine filter media effectively clarify water, but they also clog quickly and need frequent replacing.
More coarser mechanical media, while slower at cleaning, don’t clog as quickly and need less maintenance.
It’s important to consider that finer filter media, although effective, can quickly become clogged with larger debris and usually need to be discarded after use.
Continuously buying new fine filter media might become quite costly in the long run.
So, we effectively save money.
A clogged filter can block oxygen essential for beneficial bacteria in the aquarium, risking the health of the tank.
It is worth arranging mechanical filter media in the correct order.
Start with coarser media to catch big particles and follow with finer media for smaller.
This setup not only enhances filtration efficiency but also extends the life of your filter without frequent cleaning.
Often, fishkeepers use pre-filters only with coarse filter media to stop larger debris before they reach fine filter materials.
This staged filtration ensures cleaner water. Any waste not caught by the coarse filter is trapped by the fine filter.
Remember, mechanical filtration often works best alongside biological and, if needed, chemical filtration.
The finest mechanical filter media are sometimes called “polishers” because they remove nearly every particle. resulting in crystal-clear water in your fish tank.
There are generally five types of mechanical filter media, ranging from very coarse to very fine:
- very coarse filter media
- coarse filter media
- medium filter media
- fine filter media
- extra fine filter media
The different types of filter media serve specific purposes in keeping aquarium water clean.
However, you need to know that the mechanical filter media used may vary between brands.
This means that what one brand labels as “extra coarse” may be labeled as “medium coarse” by another brand.
Very coarse filter media
This type of filter media is often also called extra coarse.
Very coarse filter media should only be used in pre-filters to prevent finer filter media from becoming clogged with large pieces of waste.
Coarse filter media
Coarse filter media will also work best in a pre-filter.
They can filter out slightly smaller pieces of waste than a coarse filter but still serve their purpose effectively.
Medium filter media
Medium filter media marks the point where water clarity becomes noticeable. While it retains solid particles, it may not achieve the crystal-clear water needed for certain fish species.
Generally, you can only use a medium mechanical filter, but then you will not obtain very crystal clear water.
Most sponge filters use medium filter media.
Fine filter media
Fine filter media produces visibly clean water by capturing small waste particles. For optimal results,
For optimal results, you should use coarser filter material before fine filter media.
However, for truly remarkable clarity, you need extra fine filter media.
Extra fine filter media
Very fine filtration results in crystal-clear water by capturing particles as small as 1 micron—nearly 90 times smaller than a hair’s width.
So if you want crystal clear water, this is your go-to.
Some extra fine media can even catch microscopic parasites and bacteria.
What are the best mechanical filters?
There isn’t really one ‘best’ mechanical filter media. They’re all different and do different jobs.
Usually, when you get a filter, the media are already set up in the right order.
But, you can always change them if you want a different result.
How well your filter works depends on lots of things, like what type of filter you have, how big your tank is, and how much filter surface area there is.
It’s also important how you care for your tank and how often you change the filter media.
And make sure you put them in the right way! If you put the extra fine media before the coarse media, it might not work well.
It’s a good idea to follow the instructions from the manufacturer.
Therefore, the filter media you choose depends only on you and your expectations.
However, I will present below which products you can use as mechanical filter media.
Sponge
Sponges are one of the most popular media used in filters because they’re awesome for both biological and mechanical filtration
They’re great for cleaning up water in fish tanks.
They work in two ways: they clean out tiny particles and they also trap bigger stuff.
When you’re picking a sponge, think about how small you want the particles to be.
If you want to filter out fine particles, go for a sponge with more pores per inch (PPI), like 30 holes per inch.
But if you’re dealing with bigger waste, filter media with a lower PPI like 10 PPI will do the trick.
That way, it can catch the bigger stuff without getting clogged up too quickly.
It’s generally a good idea to stick with sponges that have PPI between 10 and 30.
Anything higher might make your water super clear, but it could also get clogged up pretty fast.
AQUANEAT Aquarium Filter Sponge Open Cell Foam Sheet Bio Sponge Filter Media Pad HMF Fish Tank Sump Divider 11″ x 10.25″ x 2″/ 23″ x 12.25″ x 2″ (11″ Lx 10.25″ W x 2″ H, Black)
Filter floss
Filter floss looks a lot like cotton candy but is actually made of densely packed polyester fibers.
These fibers work wonders in trapping tiny particles of waste and debris.
Using it is a breeze, and it fits into any filter. Typically, you’ll need to replace it after couple of weeks.
However, the exact timing depends on your aquarium type and how fast gunk builds up on your filter.
Blue Ribbon Pet Products ABLPLY7 Polyester Floss Bag Filter Media for Aquarium, 7-Ounce
Filter pad
Filter pad are one of the most popular mechanical filter materials.
It comes in various materials and thicknesses, offering plenty of customization options.
You’ll find these filter inserts in rolls that you can cut to fit your needs.
Alternatively, many brands offer pre-made pad that fit right in without any extra hassle.
Aquatic Experts Aquarium Polishing Filter Pad, Aquarium Filter Pad, Aquarium Filter Floss for Fish Tank Filters, Water Polishing Pad for Aquarium Filters
Filter cartridges
Cartridges are made to fit just one kind of filter, which means you need to buy replacement filters from this that maker forever.
They usually perform great. However, they are much more expensive than the previous ones.
Moreover, it is more difficult to adapt them to expectations. You must therefore rely on the cartridge you have.
Aqueon Replacement Filter Cartridges Large (6 pack), Ensure Even Distribution of Activated Carbon, 25% More Activated Carbon, Easy Installation
Do you need mechanical filters?
You don’t really need it and you might disagree with me now, but mechanical filtration isn’t really necessary in your aquarium.
You need to understand that mechanical filtration matters more to you, the fishkeeper, than it does to the fish.
Many of the fish you keep in your aquarium actually prefer cloudy water, filled with silt and other mechanical particles.
The reason might seem prosaic, but in such water with relatively low visibility, fish feel safer.
Moreover, potential predators have a tougher time spotting their prey.
However, every aquarist dreams of achieving the effect of crystal clear water in their tank, which adds the most decorative value.
I mean, what’s the fun in watching your fish swim in murky water? It’s basically zero satisfaction.
And who knows if they’d even be visible at all?
In conclusion
I hope you now understand everything about mechanical filtration, and any doubts you had are cleared up.
Honestly, I can’t imagine not having a mechanical filter. Especially because it lets you enjoy your tank so much more.
The best part is being able to see your tank clearly.
Plus, beneficial bacteria can thrive in the mechanical filter, so it’s really beneficial for you to use it.
