Quick, name a piece of aquarium equipment!
I’m 99.9% certain you didn’t say filter media bag.
My point is that this is likely a product that you won’t even give a passing thought to.
That is unless you have ever had to clean Purigen or activated carbon out of your aquarium because your media bag broke.
Yep, choosing a high-quality media bag is important.
Luckily for you, we tested the most popular media bags on the market, so you don’t have to.
If you want to know everything there is about this boring but useful product, you have come to the right place!
What is a filter media bag?
Filter media refers to anything you place in your filter that changes the quality of the water flowing through it.
Examples of filter media include:
- Activated carbon – removes bad smells from the water
- Zeolite – naturally removes ammonia water
- Bio balls – remove ammonia and nitrites from the water through biological filtration
If you pour any of these media into your filter, it would soon flow through your aquarium and gunk up your tank.
The problem? These media are made up of small pieces, like this activated carbon…
Due to the small size and light weight, each individual piece can be lifted up and carried by the water that is flowing through your filter – ending up in your aquarium.
Trust me when I say this:
Scooping out media that has escaped your filter is a pain in the butt!
That’s where a filter media bag comes in.
In canister filters, media bags are used to separate each filter media. For example, by using three separate bags, you could layer ceramic noodles, activated carbon and Purigen in the same filter without them mixing together.
Pretty simple, huh?
You can also buy filter media in pre-packaged bags. The problem? They are sewn shut. So once you need to replace the media, you need to dispose of the entire bag.
It is for this reason that I recommend buying media bags separately. It might cost more initially but will eventually save you money – buying filter media by the bottle is much cheaper in the long run.
What are the different types of filter media bags?
Not all filter media bags are created equally. Below are two things to be mindful of when choosing the right media bag for your filter.
1. Mesh and bag size
A filter media bag should be large enough to fit in the cavity of your filter.
Remember, the purpose of filter media is for water to flow through it. If the media bag is too small, water will be able to flow around the bag, rendering the media useless.
I recommend buying a filter media bag that is just bigger than the cavity of your filter.
But it’s not just the size of the bag that you have to worry about, but also the size of the mesh.
You see, there are many different types and brands of filter media. Some are big and chunky, like ceramic rings, while others are frustratingly fine, like Purigen.
Seriously, check it out…
It’s this fine filter media that’s the problem. If the holes in the mesh are too large, the media will escape the bag and flow into your aquarium, making a mess that needs to be cleaned up.
The fine filter media bags I recommend later this guide are all capable of holding Seachem Purigen!
But a fine mesh has its drawbacks. For one, the smaller holes reduce the amount of water that flows over the filter media. You may also find that these bags gunk up or clog quicker. It is for this reason that you should choose a coarser mesh for larger filter media.
2. How it closes
Zippers are great. Outside of the water, that is. All the media bags I tested that were “designed for aquarium use” had metal zippers.
The problem? Rust and corrosion.
Every media bag I tested that featured a zipper would eventually rust… Even the ones that were coated with paint. A tiny scratch or chip on this paint was a one-way ticket to rust city.
It is for this reason that I recommend…
Ugly but functional. I found the all-plastic design to be the best closing mechanism when it came to filter media bags.
Toss your media in the bag, pull the drawstring closed, and you are done. Simple.
Velcro was another strong performer. However, I found that over time, pieces of sand and fine filter media would get stuck in the Velcro strip.
Velcro closures on media bags were much less common. In fact, while looking for filter media bags to review, I only came across two brands.
How do you use a filter media bag?
Using a filter media bag is darn simple. Let’s walk you through the steps…
Step 1: Measure your filter
The first thing you want to do is measure the opening of your filter – both the length and width of where you will place your filter media.
Write down the measurements so that you don’t forget them!
Step 2: Find an appropriately sized media bag
Next, you want to take your measurements and find the closest-sized media bag.
Given the wide range of filter sizes, it is unlikely that you will find a media bag that perfectly fits your measurements.
So, what you want to do is find the nearest size, without going under your measurements.
Step 3: Fill your media bag
Before you fill your media bag for the first time, wash it in fresh water and don’t forget to treat it with water conditioner!
This will remove any dust and chemicals that were left over from manufacturing – you don’t want any of this stuff in your tank.
Once dry, fill your bag with your filter media. In this case, I am using bio balls.
Step 4: Place your media bag into your filter
Turn off your filter and open it. You should see a media tray. It’s here that you want to carefully place your media bag.
Give your media bag a light shake back and forth so that the media evenly spreads throughout the bag.
You want to position your bag so that the water flows through your media without any gaps.
Now, because it’s very likely the media bag you used is larger than your filter, carefully fold or scrunch the edges of your media bag to keep things neat.
That’s really all there is to it. You can now close your filter and turn it back on. See, I told you it was simple!
Best filter media bags
After testing all the main players, including Seachem and Fluval Aquaclear, and other solutions such as beer brewing bags and pantyhose, the following Weco media bags stood out above all others…
Available in a wide range of sizes, from 4″ x 8″ to 12″ x 15″, exceptional quality and at an affordable price, there really wasn’t another media bag that came close.
The fine mesh media bags were more than capable of containing Purigen and other resins without any leaking into the aquarium.
The coarse size worked great for larger media like ceramic noodles and bio balls.
I am so impressed that I will be using these media bags in my tank at home. Highly recommended!
When it came to offering value for money, nothing was better than the Pura Media Bags manufactured by Magnavore.
While they only come in one size, 6″ x 12″, these Velcro-sealed bags were perfect for keeping Purigen contained and were of exceptional quality.
If you only need a small media bag for your filter, make this your choice!
Okay, so filter media bags are definitely not a product that you will give much thought to.
But if you plan on using lose media in your filter, then this simple mesh bag is going to make your life much easier.
And if you haven’t made the switch to loose media yet, what are you waiting for? You will save money in the long run!
What media bag do you use in your filter? Let me know in the comments below!
I’ve been keeping fish for over 30 years and currently have 4 different aquariums – it’s an addiction. I’m here to teach you everything there is to know about fishkeeping.
I also use this site as an excuse to spend lots of money on testing and reviewing different aquarium products! You can find my reviews here.