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The Best Filter Media For Reef Tank Setups: Sumps, Canisters & More

Reef tank filtration can sometimes be challenging to get right. So let’s look at how to choose the best filter media for reef tanks based on your setup.

By Julie Millis
Last updated on

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Best Organics & Phosphate Removal

Chemi Pure Elite tub
Chemi-Pure Elite

Best Reusable Chemical Media

Seachem Purigen

Alternative Organics Removal

Fluval Carbon
best filter media for reef tank

Reef tanks are amazingly beautiful, but when it comes to keeping the water in perfect condition it can be a challenge, especially if you are a beginner! And a large part of that is choosing the best filter media for reef tanks.

Depending on if you have a built-in filter system, or use a canister or a sump, the filter media you need can vary. We recommend Chemi-Pure Elite as a good all-round chemical media, as it controls organic pollutants and phosphates to reduce algae.

But there are many specialized mechanical, chemical, and biological media available for reef tanks. That’s why we’ve reviewed a wide range of options here to cover several scenarios depending on your setup. 

So let’s dive straight into the world of reef tank filter media!

  1. Best Reusable Chemical Media: Seachem Purigen
  2. Best Combined Organics & Phosphate Removal: Chemi-Pure Elite
  3. Best For Alternative Organics Removal: Fluval Carbon Filter Media
  4. Best For Biological Filtration: Fluval Biomax Filter Media
  5. Best For Natural Phosphate Control: Brightwell Aquatics Chaeto GRO
  6. Best For Alternative Phosphate & Silicate Removal: Fluval Clearmax
  7. Best For Reef Tank With Sump: Aquatic Experts Filter Socks
  8. Best Cut-To-Fit Filter Pad: Aquatic Experts Filter First Aquarium Pad

Best Filter Media For Reef Tanks Reviewed

Choosing the best filter media for reef tanks depends on your filtration system. We’ve assessed the best mechanical, chemical, and biological media suitable for different types of saltwater filter system, along with specialized options if you have a sump set up.

1. Seachem Purigen


  • Filtration Stage & Media Type: Chemical stage, synthetic fiber resin
  • Media Purpose: Ammonia, nitrite, and nitrate removal
  • Most Effective In: Canister, HOB filter, media reactor
  • Best For: Reusable Chemical Media

Purigen is a synthetic polymer that is excellent for removing nitrogenous organics including ammonia, nitrite, and nitrate from your reef tank. And like activated carbon, it really polishes your water leaving it crystal clear for viewing your marine life.

Whilst you can use it in a media reactor it’s not essential, and will work just as well in a HOB or canister filter using a fine mesh bag. It starts as an off-white color but as it becomes exhausted it eventually turns black, which is really useful as you’ll know exactly when to change it.

And even better is you can recharge your Purigen by soaking it in a 1:1 bleach solution overnight, so you can re-use it again and again. It will last around 3 months between recharges. 

Overall Purigen is an excellent ammonia, nitrite, and nitrate filtration resin that gets deserved praise from customers for its ability to leave your water crystal clear too!

2. Chemi-Pure Elite

Chemi Pure Elite tub


  • Filtration Stage & Media Type: Chemical stage, activated carbon, ion-exchange resins & ferric oxide
  • Media Purpose: Ammonia, nitrite, nitrate, phosphates and silicates removal
  • Most Effective In: Canister, HOB filter, media reactor
  • Best For: Combined Organics & Phosphate Removal

There are several excellent products in the Chemi-Pure line, but Chemi-Pure Elite has to be our favorite. As well as acting to remove ammonia, nitrites and nitrates it also absorbs phosphates, so preventing algae in your tank whilst keeping it crystal clear in one product!

Using the supplied nylon bag, place approx. 6.5 oz of the pellets for up to 25 gallons in your canister or HOB filter and it will work for around 4 months. You don’t need to use a media reactor, and you can even use it in a sump as long as you have enough water flow. 

As well as tackling algae, and leaving clear water, Chemi-Pure Elite helps reduce odors in your tank. And while one or two owners have reported it can emit a dark cloud when first used, this is normal and will clear quickly. Just bear in mind it is shipped wet and needs rinsing before use.

Overall an excellent combined organics and phosphate remover that receives high praise from customers and has been providing great results for years!

3. Fluval Carbon Filter Media


  • Filtration Stage & Media Type: Chemical stage, activated carbon
  • Media Purpose: Ammonia, nitrite, and nitrate removal
  • Most Effective In: Canister, HOB filter
  • Best For: Alternative Organics Removal

Fluval produce really effective filter media, and Fluval Carbon is no exception and fantastic for reef tanks. The 6.1 x 4.7 x 0.9 inch bags will fit most medium to large canisters and HOBs. And you can also use them in your sump, although they work best where the flow is higher.

The fine granules have a high surface area meaning it does a great job at absorbing ammonia, nitrites, and nitrates, which will help keep your reef tank odorless and your water color crystal clear.

It’s also important if you keep coral, as carbon can remove the toxins your corals sometimes release as a defense mechanism. Without their removal, these toxins can harm other marine life in your aquarium.

As it’s low-ash carbon we found it doesn’t get too dusty or messy. And the fine nylon bag holds in all the carbon well, again making it easy to handle with less mess. Fluval Carbon gets great feedback from users overall for its ability to clear your water and great value price!

4. Fluval Biomax Filter Media

Fluval Biomax biological filter media


  • Filtration Stage & Media Type: Biological stage, ceramic bio rings
  • Media Purpose: Support growth of beneficial bacteria
  • Most Effective In: Canister, HOB filter
  • Best For: Biological Filtration

When it comes to reef tanks, we’d always recommend keeping live rock in your main tank or sump as they are one of the best ways beneficial bacteria can colonize your tank. But ceramic media is a fantastic addition or alternative, and Fluval Biomax is an excellent choice.

Unlike some smoother ceramic media, Biomax has a rough porous texture giving more surface area for beneficial bacteria to colonize. And the hollow center of each ring allows more contact with your wastewater so these bacteria can remove more ammonia and nitrites.

Each Biomax ring is quite large, at 0.75 x 0.7 inches, but it will work well in medium to large HOBs and canisters, and you can also use it in your sump. Although Fluval recommends you change the media every 6 months it can last a lot longer if you rinse it when it becomes clogged.

Overall, this is a great value option and many users praise Biomax for its ability to help stabilize their water parameters keeping their tank clean and clear.

5. Brightwell Aquatics Chaeto GRO


  • Filtration Stage & Media Type: Biological stage, macro-algae (chaetomorpha) growth
  • Media Purpose: Support growth of chaetomorpha algae to take up phosphates
  • Most Effective In: Sump (refugium)
  • Best For: Natural Phosphate Control

If you own a larger reef tank, one of the most effective and natural ways of dealing with excess phosphates is to grow macro-algae by sectioning part of your sump into a refugium. ‘Chaeto’ (or chaetomorpha) is one of the most effective phosphate absorbing macro-algae.

Chaeto GRO is an excellent supplement to support the growth of chaetomorpha. It contains 13 nutrients but without any phosphates, so will cause your Chaeto to grow healthily and encourage more uptake of phosphates from your water, preventing algae in your main tank.

Many users report that Chaeto GRO caused their Chaeto to grow faster, denser, and darker with just a very small dose. And many noticed falling phosphate levels and no adverse effects on other marine life or invertebrates.

6. Fluval Clearmax

Fluval Clearmax Phosphate Remover 3 pack


  • Filtration Stage & Media Type: Chemical stage, synthetic resin
  • Media Purpose: Removal of phosphates, silicates and nitrites
  • Most Effective In: Canister, HOB filter
  • Best For: Alternative Phosphate & Silicate Removal

Fluval Clearmax is another excellent choice for the removal of phosphates, both in freshwater and reef tanks. Not only is this important to prevent algae in your tank, but if you keep corals it helps their growth as high phosphate levels can stunt their skeletal development [1].

Clearmax will also remove silicates and nitrites from your water which are harmful to your marine life if allowed to build up. Bear in mind though it won’t remove nitrates from saltwater, so use it with another organics remover if are trying to reduce your water change frequency. 

As with many types of Fluval media, Clearmax comes in fine mesh 6.0 x 4.7 x 0.9 inch nylon bags that will fit well in a good size canister or HOB filter, and make handling easy and mess-free. Just be sure to rinse the media before adding it to your filter to remove any dust.

Overall another great Fluval media that many reef tank owners praise for its value, long-lasting effectiveness, and ability to keep their tank clear and algae-free!

7. Aquatic Experts Filter Socks


  • Filtration Stage & Media Type: Mechanical stage, welded edge filter sock
  • Media Purpose: Mechanical removal of detritus and fine particles
  • Most Effective In: Sump
  • Best For: Reef Tank With Sump

If you own a larger reef tank of perhaps 55 gallons or above and run a sump, the most effective first filtration stage is to use a filter sock on the incoming drain pipe. And these felt filter socks from Aquatic Experts are our pick for the most effective.

We prefer the welded edge filter socks, although you can get the normal seams too. But the advantage of the welded edge is you don’t get any stitches or threads coming loose in your sump and getting into your water.

At 200 microns, they are great for filtering even small particulates from your incoming wastewater. But as the mesh is not too fine it won’t clog as quickly as smaller micron filter socks, helping to reduce your maintenance.

Like many filter socks, you’ll need to change them around once a week. And the plastic ring-opening and inner handle make this quick and easy. Overall owners praise these as great value filter socks that are easy to clean and durable given the price.

8. Aquatic Experts Filter First Aquarium Pad


  • Filtration Stage & Media Type: Mechanical stage, filter pad
  • Media Purpose: Mechanical removal of detritus and fine particles
  • Most Effective In: Canister, HOB, and most filter types
  • Best For: Cut-To-Fit Filter Pad

The Filter First filter pad roll from Aquatic Experts is made up of a thick, looser top layer bound to a much denser bottom layer, trapping both large debris and fine particulates. This makes it really effective at removing organic solids before your water moves to your next filter stage.

We found it very easy to cut and shape, and you can get it to fit most filter types easily, especially canisters and HOBs. It’s also very durable and will last around 2 months if you rinse it once every one to two weeks, making it cost-effective too.

While one or two reef tank owners have reported it has caused their protein skimmer to overflow when first used, the majority have not seen this issue and instead praise it for leaving their tank clean and clear.

Common Reef Tank Filter Types

The best filter media for reef tanks depends on your aquarium and the type of filtration system you use. Whilst we could go into much more detail about saltwater and reef tank filtration, let’s take a brief look at some of the common methods:

Orange and white clownfish
  • Sumps: A sump is one of the best reef tank filter systems you can use, but it’s also the most expensive and complex to set up. It’s a separate, smaller tank containing various filter media, where wastewater is filtered before being returned to the main aquarium. 
  • Canister Filters: Another good choice for smaller tanks. These are powerful external filters that usually sit under the aquarium where they pump out the water, process it through several filtration media stages, and then return it to the tank.
  • Hang On Back (HOB) Filters: These are sometimes used as the primary filter in a smaller tank, but often as an additional filter in a larger reef tank. They hang on the back of the tank and pump water through the filter media before returning it. 

Types Of Reef Tank Filter Media

A reef tank will typically contain saltwater fish, coral, live rock, and perhaps other marine invertebrates. With all these different aquatic animals it’s particularly important to find the best filter media for reef tanks.

Let’s look at the main filtration stages in detail along with some of the best types of media to use in a reef tank for each stage.


Mechanical filtration tends to be the first stage in all filter systems and is simply the removal of particles and detritus from the water. This stops the debris from reaching your chemical or biological media and clogging them up, which would make them less effective.

Some of the best types of mechanical filter media for reef tanks are:

  • Filter Socks: If you run a sump, these tend to be the best choice. They attach to the drain line so the waste tank water passes through them first. A 150 to 200 micron filter sock will remove most particulates without clogging up too quickly.
  • Filter floss, Pads, And Sponges: These tend to be the main mechanical media for canisters, HOBs, and other filter types. And the advantage with canisters and HOBs is you can often use a quality filter sponge that can be customized to fit, rather than being constrained to specific cartridges.


Reef tanks need to keep similar water parameters as freshwater tanks under control, such as ammonia and nitrites. But other parameters can be particularly important to maintain correctly too, like nitrate and phosphate.

Here are some of the best chemical filter media types for reef tanks to help manage various toxins and pollutants:

  • Carbon: Carbon (or activated carbon) often comes as granules and will remove organic pollutants like ammonia, nitrite, and nitrate, as well as tannins that can discolor your water. You can use it in a mesh bag in your filter or sump, or in a media reactor.
  • GFO And Aluminia Oxide: Granular ferric oxide (GFO), alumina oxide, and similar products remove phosphates and silicates from your water. This is important as phosphates (combined with nitrates and light) can cause algae outbreaks [2].
  • Purigen: This is a synthetic media that works best in your filter or media reactor. Similar to carbon it absorbs a large number of impurities including ammonia, nitrites, and nitrates. It also polishes your water in the same way carbon does.
  • ChemiPure: ChemiPure is a mix of activated carbon and ion-exchange resins that again removes organic pollutants from your water. ChemiPure Elite also contains ferric oxide and will help with phosphate and silicate removal too. It’s suitable for use in your canister filter, HOB, or sump.


Biological filtration is arguably the most important filtration stage in your reef tank. The purpose of biological filter media is to provide the right environment for beneficial bacteria to colonize.

These consist of nitrifying bacteria that process ammonia via the nitrogen cycle, and denitrifying bacteria that process the resulting nitrates.

Here are some of the best biological filter media types you can use in your reef tank:

  • Live Rock: Using live rock in your reef aquarium, and in your sump, is one of the best biological filtration methods. Formed from the calcified skeletons of dead corals, it provides the best media for both nitrifying and denitrifying bacteria to inhabit. 
  • Ceramic Media: Great for use in canisters and HOB filters, ceramic media are highly-porous rings giving plenty of surface area for beneficial bacteria to colonize.
  • Bio Balls: These plastic balls are perfect for canisters and HOBs. They provide great surface area for beneficial bacteria to grow on and help agitate the water to oxygenate it, in turn helping aerobic nitrifying bacteria to thrive. 
  • Macro Algae: If you own a sump, you can set part of it up as a refugium to grow macro-algae. This is a natural way of removing phosphates from your water as the macro-algae uses it for nutrients.

How To Choose The Best Filter Media For Your Reef Tank

Whilst there are several ways you can achieve the right filtration in your reef tank, it’s important to consider the following key factors when choosing your approach.

Yellow foxface rabbitfish

Consider The Needs Of Your Reef Tank

Unlike a simpler fish-only (FO) saltwater tank, a reef tank can contain not only fish, but also invertebrates, live rock, and corals. Not only does this mean a lot of waste in your water, but you also have a wider range of marine life that are sensitive to the water parameters.

For that reason, the best filter media for reef tanks often depends on the size of your tank and its inhabitants. You should at least have some combination of mechanical, chemical, and biological filter media as described above. But you may not need every single one in all scenarios.

If you own an all-in-one nano tank, for example, it’s likely to come with built-in filtration which uses filter pads, a form of carbon, and some ceramic media. But with a large reef tank, you should look to use a sump with live rock for biological filtration.

Consider Your Filter Type

Bear in mind that not all media will fit or be as effective in every type of filter system. For example, phosphate removers like Seachem PhosGuard work best in a canister filter, HOB, or media reactor where they get a high-water flow, rather than in a sump.

Similarly, internal filters in a smaller reef tank will often only take mechanical cartridge pads designed for that particular filter. That’s another advantage of a canister or HOB as they are much easier to customize with your own media.

Type Of Material

Depending on what type of filter media you are buying, whether mechanical, chemical, or biological, it can be made of many different materials. For example, some types of biological filtration media can be either plastic, ceramic, or glass.

When it comes to choosing the best filter media for your reef tank, always check that the product you are looking at won’t adversely affect your water, such as causing pH changes. Look for high-quality products by checking Amazon reviews to assess this. 

Size, Shape, And Porosity

Filter media for reef tanks can come in many different shapes and sizes. Carbon inserts, for example, can sometimes be designed to fit a specific HOB filter. Similarly, some biological ceramic media can be bigger than others and so better for large canister filters.

It’s also worth thinking about shape and porosity. Chemical media with a larger, more porous surface area will have maximum contact with your water so allowing it to be more effective. And the more porous your biological media, the more surface there is for beneficial bacteria to grow.

Price And Effectiveness

The best filter media for your reef tank may not always be the most expensive, and it does depend on the type of media you need. Some chemical media, for example, can be more expensive than a simple filter sponge.

But do consider longevity when it comes to price too. Ceramic media can last for many months, for example, making things more cost-effective in the long run. And whichever product you choose, remember to check customer reviews to gauge quality and effectiveness.

Our Verdict

Overall, we found Chemi-Pure Elite to be a great all-in-one chemical media for controlling both organic pollutants and phosphates to keep your reef tank clean, algae-free and safe for your fish and other marine life.

But using Fluval’s products together like Fluval Carbon and Fluval Clearmax can do a great job too, and offer good value.

Whichever you choose, bear in mind the best filter media for reef tanks can vary depending on your setup. But whether you use a HOB, canister, or a sump, you’ll find all you need within the choices here!


We’ve answered the top frequently asked questions when it comes to finding the best filter media for reef tanks. Take a look below!

Do You Need All Types Of Media For A Reef Tank?

You should always use some form of mechanical, chemical, and biological filtration in your reef tank as a minimum. A large reef tank is likely to need more media types than a small nano tank.

What Order Should You Place Your Media In The Filter?

As with all filters, start with your mechanical media to capture particles and debris before it can clog your other media. Biomedia is usually placed last before your water return.

How Often Should You Clean Your Filter Media?

Reef tanks usually need their filtration systems cleaned more frequently than freshwater tanks, and at least weekly, but the exact timing depends on the media as per the product instructions. 

How Often Should You Change Your Filter Media?

Again, it really depends on the media type. Filter socks in a sump for example will need changing weekly. Chemical media can last 1 to 2 months or even longer. 

Photo of author
Julie Millis
Julie has been involved in aquatics for over 15 years. She is passionate about freshwater and saltwater tanks. Julie loves helping with all your fish-keeping questions!

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