Aquarium Filter Floss 101: Info + Our Recommendation

Aquarium filter floss is foreign to a lot of new aquarists. With so many things to learn, beginners naturally spend their time on the most important stuff (like the filters themselves).

Over time, they start to get more comfortable with the whole fishkeeping process. It’s exciting to finally feel like you know what you’re doing!

But then they hear about filter floss and feel like beginners all over again.

You see, filter floss is one of those things that’s extremely useful but not crucial enough to get talked about by everyone. In fact, there are plenty of rather experienced aquarists who don’t really know much about it either!

So that’s where this guide comes into play.

In it, you’ll learn everything you need to know about aquarium filter floss. What it is, benefits, and which one we recommend!

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What Is Aquarium Filter Floss?

Let’s start with the basics.

Filter floss is basically padding that’s designed to catch larger waste and debris in your tank. It’s usually built with one sturdy side so water can flow through it effectively without bending it.

It is flexible and can be cut to fit a wide variety of filters. This means if you want to include filter floss in your tank it’s highly unlikely that your filter won’t be compatible.

There are a number of brands out there that offer basically the same product, with a few little differences. This makes finding the best one a little tricky (we share our favorite at the bottom of the guide).

The Benefits

So what are the benefits of using filter floss in your aquarium?

Well as you may have guessed, the reason people include this in their tank is for the sake of improving water quality. That’s always the name of the game, and some owners swear by it.

inTank Aquarium Filter Floss - 600 Square Inches

  • Double-layered pads catch large and fine detritus
  • Thicker layer provides backing for stability
  • Won’t break apart and get eaten by your fish
  • Easy to cut and change

The nice thing about it is that you can quickly make a positive impact on the cleanliness and clarity of your water by adding filter floss to your tank. While other changes take a while to set in, filter floss is the exact opposite.

In fact, if you add high-quality filter floss to your tank it shouldn’t take more than a few days for you to see the impact.

Another benefit that filter floss can bring to an aquarium is a reduced load on the rest of your filtration. The floss handles a lot of the heavy-lifting and acts as a bouncer outside a club. It catches so many unwanted waste particles upfront that your other filtration can coast.

This means you’ll get more mileage out of your other equipment and save time in the long run. When you compare it to cleaning or fixing a filter, replacing floss is unbelievably easy to do.

Author Note: It’s pretty cheap as well. Even though you’ll need to change it quite often (more on that in the section below), it still won’t break the bank.


Even though we’ve talked about the benefits of adding filter floss to your aquarium, there are some downsides you should be aware of.

In our opinion, these are blown way out of proportion by the anti-floss crowd. But it’s up to you to decide if they’re enough to turn you away or not.

The main downside of using filter floss is their potential to raise the nitrate level in your tank. Since these pads are grabbing a lot of waste and debris they can quite easily start to create nitrate that impacts the rest of the life in your tank.

So how do you get around this?

The answer is actually quite simple. In order to stop your aquarium filter floss from producing nitrate at a rapid rate you simply need to change them out regularly.

It’s really that easy.

The optimal number of changes per week really depends on the bio load and tank size, but you’re likely going to be swapping it out every 5-7 days. Waiting any longer than that is a bit too risky.

When you consider just how easy it is to change out filter floss, it’s really not a big deal. However, some people feel differently. They don’t like the possibility of added nitrate and prefer to let their other filtration do the work.

It’s ultimately up to you. In our opinion, it’s so cheap and easy to test that you may as well give filter floss a shot before deciding if it’s for you or not.

Author Note: Some aquarists think that the frequent changing of filter floss makes it more expensive than the upfront price might indicate. This ultimately comes down to your budget but in our opinion, it’s still rather affordable (our favorite brand gives you quite a lot for a very minimal price).

How To Add It To Your Tank

The funny thing about aquarium filter floss is it’s really easy to use, but many people don’t realize it. Since there are so many conflicting opinions about it and a general lack of info about it online, you end up with some aquarists thinking it’s some fancy piece of equipment that has a learning curve.

And that couldn’t be any further from the truth.

When you start using filter floss you’re basically just putting it somewhere in your filter. It’s really as simple as that.

Once you have some to use, here’s how the process looks:

First, you should measure the area of your filter where you’ll be adding the floss. Depth is less of a concern as length and width. Since filter floss can be used in a wide variety of filters, it’s on you to size it for your particular equipment.

Now that you have the dimensions of the area where you’ll be placing it, it’s time to start cutting. Simple take some scissors or a box cutter and cut the padding so it fits. Make sure there aren’t any loose bits that could separate and float into the tank.

Author Note: Make sure your scissors or blade are clean before doing this. This is a step that many people skip in this process, but we feel it’s important. You never want to introduce unwanted waste or chemicals to your tank!

Once you have it cut to the appropriate size, simply stuff it in the previously measured spot in your filter. You’re done!

It’s a good idea to write down the dimensions somewhere so you can quickly cut more when you need to change it in the future. Another option is to cut a bunch all at once so you have a stash to pull from (we prefer that).

A tip that’s worth mentioning is that you should try and be as efficient as possible when cutting filter floss. This will allow you to make the most of what you purchase and save a bit of money. 

You can also save the remnant pieces and combine them so you’re not wasting anything. A lot of aquarists don’t do this because it doesn’t seem like it would make much of a difference, but it adds up!

Our Favorite Brand

Now that you know all about aquarium filter floss and how to use it, we figured it would be helpful to share the brand we recommend.

inTank Aquarium Filter Floss - 600 Square Inches

  • Double-layered pads catch large and fine detritus
  • Thicker layer provides backing for stability
  • Won’t break apart and get eaten by your fish
  • Easy to cut and change

We’ve heard from many tank owners that it can be hard to tell the difference between different filter floss brands and products. That’s because on the surface they all look very similar.

We’ve tried a bunch of filter floss over the years and this one by inTank is definitely our favorite.

Here’s why:

First off, the build quality is superb. These are bonded pads that hold up over time and can be placed in a wide variety of locations without falling apart. It gives you peace of mind knowing that your fish aren’t going to be eating chunks of floss thinking it’s food.

Half of the floss is thicker which helps to catch smaller detritus and doubles as a support layer to handle all levels of water flow. Despite the durability of the padding, it’s still super easy to cut however you see fit.

In our experience, we found that the water quality looked a lot nicer after using this filter floss compared to others. Not only did the pads seem to catch more waste and detritus, but the water was also crystal clear.

What really seals the deal for us is that the price is extremely competitive. Despite it delivering top of the line results, it’s priced just like most other quality filter floss.

Usually, when it comes to aquarium equipment there are certain products that are without a doubt the best on the market (like the Fluval FX4 canister filter). But you usually have to pay a lot for the difference in quality.

That’s not the case with this filter floss. In our opinion, you’re getting the best product available for a very standard price. The reviews of other customers echo our thoughts as well.

What’s not to like about that?

Closing Thoughts

By now you should have a good understanding of aquarium filter floss and what the benefits are. If you’re someone who agonizes over water quality (no matter if it’s a functional interest or an aesthetic one) then you owe it to yourself to give it a shot.

You’ll be amazed at the kind of gunk it will pull out of your water. The reduced wear on your other filtration will be something you’ll notice as well.

Personally, we’re in the pro-filter floss camp and plan on using it in many of our own tanks for the foreseeable future.

If you still have any lingering questions about the benefits or the best way to add it into your existing filter, drop us a line. Talking shop with other aquarists is all part of the fun when it comes to this hobby!

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