Best Canister Filters: Which One Will Transform Your Fish Tank Water?

What is the best canister filter?

Wouldn’t it be great to have that clear aquarium water that we see in professional aquariums? The fish look great in their tanks.

Upgrading to a canister filter could unravel the secrets of crystal clear water. This gives us another question to answer though:

What really is the best canister filter to transform my fish tank?

There are so many good canister filters out there and this makes the job of choosing the right one for your current or new tank a difficult task.

In this guide, I am going to demystify canister filters and show you my recommendations. By applying these tips you will be able to choose the best canister filter for your tank.

What Is A Canister Filter?

Let’s kickstart this guide with a definition of what a canister filter actually is. I mean we can guess it will filter your tank but let me give you a proper definition.

A canister filter will suck the water from your tank via an intake tube or a sieve. From there the aquarium water is passed through the chosen filter media which is housed in a pressurized canister. Once the water has passed through this special canister it is then pumped back into the fish tank via a spray bar or just a simple tube.

As the filtration is carried out in the canister the filter can be hidden out of sight. This means you will not take away from the pretty look of your aquarium. You will not reduce that precious swim space either.

When used with smaller tanks these can be a bit of an overkill. If your aquarium is 40-gallons or larger I would consider upgrading your filter to a canister for a lower maintenance filtration system. Anything less than that will do just fine with a Hang On Back Filter like the AquaClear 70.

For bigger aquariums your filter has to work harder so choosing a canister filter would be a great option.

ImageNameAquariumsRatingCustomer Reviews
Fluval Canister Filter, FX6 FilterFluval Canister Filter, FX6 FilterSaltwater or Freshwater up to 400 GallonSuccessful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
EHEIM Classic External Canister FilterEHEIM Classic External Canister FilterSaltwater or Freshwater up to 90 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Hydor Professional External Canister FilterHydor Professional External Canister FilterSaltwater or Freshwater up to 150 GallonSuccessful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
Marineland Magniflow Canister FilterMarineland Magniflow Canister FilterFresh & Saltwater up to 100 GallonsSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Penn Plax Cascade Canister Aquarium FilterPenn Plax Cascade Canister Aquarium FilterSaltwater or Freshwater up to 200 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
SunSun Hw304B 525GPH Pro Canister FilterSunSun Hw304B 525GPH Pro Canister FilterSaltwater or Freshwater up to 150 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Eheim Pro 4 Canister FilterEheim Pro 4 Canister Filter
Saltwater or Freshwater up to 160 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Cobalt Aquatics EXT Canister FilterCobalt Aquatics EXT Canister Filter
Salt or Freshwater up to 55 Gallon Successful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
API Filstar XP Canister FilterAPI Filstar XP Canister FilterSalt or Freshwater Safe. For tanks up to 265 GallonSuccessful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
EHEIM Ecco Pro External Canister FilterEHEIM Ecco Pro External Canister FilterSaltwater or Freshwater up to 80 GallonSuccessful Aquarium give this tank 3.5 out of 5 starsCheck It Out!

Is The Fluval FX6 Canister Filter Worth The Higher Price?

When it comes to aquatic products Fluval really does deliver. With the Fluval FX6 Canister Filter they have still not let me down. It has been improved in many ways to keep it in the premium canister filter range.

Fluval Canister Filter, FX6 Filter

From the outside, you have a filter that has been designed to fit most aquarium cabinets. So it can still be hidden out the way. The size has been optimized so that it can filter humongous amounts of water.

The FX6 can handle an aquarium of up to 400 gallons.

This is a huge amount of water.

Since the upgrade, Fluval has re-tuned the Smart Pump Technology circuit board. This means a quieter and more efficient filter. It can also monitor the change in resistance and flow that the filter is putting out a whole lot better.

As well as these technology advances the Fluval FX6 canister filter has been designed to make cleaning and maintaining a breeze. From special little stop valves and safe seals to rotating valves so that you can reach those hard to reach areas with ease.

If you have a memory like me, then the new water change and maintenance dials will be your savior. You can set them when you do your maintenance and you will have a reminder when the next one is due.

It would be good if they were electronic so that they would buzz or something when it was due. However, I still think it is a nice addition.

It has three media trays that can hold huge amounts of media. The media has a sponge pre-filter surround to boost the mechanical filtration.

If you are looking for an easy to use, durable, efficient and quiet canister filter that can keep your water crystal clear then the Fluval FX6 is a step in the right direction. Not to mention, Fluval’s customer support is second to none.

If the price is an issue the SunSun Canister filter (see further down on the list) is a great alternative. The higher price is definitely money well spent.

The Time-Tested Eheim Classic Canister Filter 

Eheim filter always seems to make it onto best filter lists. In fact, on this list, I am introducing you to three different models.


Because they are a favorite canister filter brand. This very filter model has been around for over 15 years and it is still classed as one of the best filters for your fish tank. Eheim has stood the test of time and so has the Eheim Classic Canister filter.

eheim classic 250 best canister filter

It is made from a durable high-quality fish safe material. Unlike most filters, on the market, the Eheim Classic filter features stainless steel clamps that secure the motor while the filter is running. Most other manufacturers use plastic clamps that can snap easily.

There is no bypass feature on this model which means you will have to keep a close eye on the maintenance. If this is an issue you could always take the Eheim Pro Canister filter which has this technology.

The classic filter comes with the double tap feature that most of Eheims filters come with. This means when it comes to maintenance time you can disconnect the canister without having to disconnect the plumbing.

This filter is a breeze to use with features like this.

The flow rates on this filter are another great feature and it only uses 20 watts of power. The rate goes all the way up to 900 GPH on the 1500XL model.

If this is your first canister filter be sure to watch the video below on how to set this model up. Customers have stated that the instructions are pretty poor. Is this a big problem… not when you have a video like this to follow:

The Eheim Classic canister filter is a great filter if you are new to canister filters. When your new filter arrives it will come with everything you need so that you can unbox, setup and go!

Hydor Professional Canister Filter: The New Kid On The Block

Next is the Hydor Professional 350 Canister Filter, one of the newer models. Hydor, however, is not a new brand, they have been in the aquatic industry since 1984. They have been trying and testing things for years.

The Hydor Pro canister filter is the result of all their efforts.

Hydor Professional External Canister Filter

As for the filter itself, you can really get a sense of quality with its solid design. The impeller spins on a ceramic shaft, this alone will help increase the lifespan of the filter.

Another great design feature is that the O-ring is recessed in the motor which will stop it getting knicked or falling out.

As well as life increasing features this model has built-in rubber feet. You don’t need to worry about them falling out. This helps reduce the noise. Speaking of noise, this filter is pretty much silent.

The flow rates on this range will not disappoint. On the smaller end, you can filter your tank at 190GPH and 345GPH at the higher range.

On the top, you have an auto prime button, so it really is a plug-in, plumb in and go filter. The two in and out hose attachments are solid and also located at the top. These can be rotated easily making it easier to set up and maintain.

Even when the canister is filled with water.

On the whole, this is a great, easy to use and silent canister filter. As soon as you unbox you have all the necessary accessories to get you up and running. When you are set up make sure that the media trays are stacked properly. If it isn’t your filter might bypass.

Marine Magniflow: Is It The Best Canister Filter?

Next, we move onto the Marineland Magniflow Canister Filter. Marineland is another strong aquatic brand and has been around for a good number of years. The Marineland Magniflow is an upgrade to their earlier C Series range.

Marineland Magniflow Canister Filter

One of the updates from the earlier range is the priming button. In the newer model, it is a lot more robust and easier to use.

That’s not all though, they have upgraded the design of the motor head. Now instead of having to line up the clips, we have four clips. The cool part is that the motor head will fit into the canister in any way.

No more fiddling about and wondering which way does it go.

When you unbox this filter you are given filter media to fit in the four baskets. Baskets help to keep the media more secure than trays.

For mechanical filtration, we are given filter pads and coarse filter pads. For the biological part, we have bio balls and bio rings to create a large surface area. This is really important as the bigger the surface area, the bigger the good bacteria colony can grow.

The filter media baskets fit in the canister anyway too. You do have to line up the internal lift tube though. If this isn’t properly aligned the filter will bypass.

The models are similar to the C Series. With the Magniflow you have:

  • 160 – 160gph and it is suitable for a 30-gallon aquarium
  • 220 – 220gph and it is suitable for a 55-gallon aquarium
  • 360 – 360gbh and it is suitable for a 100-gallon aquarium

Before you can plug this system you need to remember to install the O-ring to the motor head and remove all the packaging from inside the canister. Apart from that you are pretty much good to go.

Here is a video to show you how to get going with this filter:

The Penn Plax Cascade Canister Filter: The Budget Filter In My Eyes

The Penn Plax Cascade canister filter seems to make all the top list post but it doesn’t get nearly as much love as some of the others.

Does that make it a bad choice of filter for your tank?

Penn Plax Cascade Canister Aquarium Filter

In my opinion, it has a lot of great features and does get the job done. If you are looking for a low priced option then this is it. It is priced the same as a top range hang on back filter but is a hell of a lot more powerful.

The biggest downside, in my opinion, is the lack of any decent bio media. It is a 3 basket set up and comes with floss and coarse filter pads as well as activated carbon. If you do choose this setup I would suggest you also purchase bio balls or ceramic tubes.

This will add more surface area for your good bacteria. That is the awesome thing about canisters you can chop and change the media, they are really flexible.

It does seem easy to use from the videos I watched which are a big bonus. All the pipes and tubing is there. You could easily set it up and then add the bio media at a later date. You will get better results with the bio media though.

If this is your first canister filter then watch a video like this one to learn how to set it up:

The instruction documentation is quite messy, it comes with a big poster like document. Use a decent video to learn how to set it up.

From other reviews, it isn’t the quietest but from the reviews, I have seen it isn’t much difference in noise. It is maybe a few decibels louder.

This a great beginner filter but if you can afford something like the Marineland Magnaflow I would definitely consider it.

SunSun/Aquatop HW-404B Canister Filter: In Two Minds About This One

With this filter, I have heard so rave reviews about it being on par with the Fluval FX6. However, I have also heard of it burning and been made of cheap material. If you choose the SunSun 404B Canister Filter then here is what I think.

SunSun 404b Canister Filter

When your filter arrives you have everything you need to get going, all the plumbing and all the media. It comes with fine floss, medium, and coarse pads. This is a five stage set up and you have enough media for your setup.

As well as the pads you have bio balls and rings to add more surface area. These are by SunSun/Aquatop and all the reviews seem pretty good with regards to the media. It also comes with some activated carbon if that’s your thing.

When it comes to plumbing make sure you have your Weetabix that morning. The vinyl in and out tubes are very thick, which isn’t a bad thing but it does make it a struggle to connect it all up. The good thing is that once you plumb it in you can easily disconnect the canister for maintenance.

The 9V UV light is where most of the negativity comes in. It is supposed to reduce algae bloom but so will good filter maintenance. If you leave this switched on it can burn the plastic.

Not good at all!

My fix would be to leave on for 2-3 days and then off for 2-3days. Most people who have done this have been more than happy with the effectiveness of the bulb. Be aware that the on light for the UV bulb looks faint and when you open the canister the bulb goes off. Don’t let this make you think it’s broken.

Now for the flow rates!

I would suggest you take the advertised flow rates with a pinch of salt. I think this would be fine for a 50- 60 gallon but wouldn’t use for a bigger aquarium.

I would say if you are on a budget it is a decent filter, the burning freaks me out a bit but you don’t need to use the UV bulb. It is easier than the SunSun 304B to prime and has a handy handle.

If you want to see how to set it up here is a quick video:

Eheim Pro 4+ Canister Filter: Nailed It

We are now coming back to Eheim for the next filter on our list. This time we are looking at their PRO series. The Eheim Pro 4+ Canister Filter is the upgraded version of the ever popular Pro 3 series.

Eheim Pro 4 Canister Filter

The most noticeable change with the 4th edition is that they have ditched the green color. In my eyes, this is a big improvement.

I wasn’t a fan of the green!

In the Pro 4+ range everything has been changed to black. The canister, the tubes and the inlets and outlets. This filter now has a sleek and clean look. In the aquarium, this black color blends in well and looks awesome.

Like most good canister filters the Eheim Pro 4+ comes with some decent filter media. We have the Mech Pro media which has a unique ribbed structure which allows much better colonization. Not to mention, it is also much better at trapping dirt particles.

We also have Bio Mech has an optimum pore structure with 400 squared meter/liters. This is an incredible surface area for bacteria!

Another big advance is the Range Extender. 

Let’s say you are going to be unable to do your maintenance at the correct time. You know your tank needs it but you just can’t get a minute. Well, you can press this button and it will push the water through the coarse media only. It will bypass the fine media. This is a godsend as the coarse media is much easier to clean.

Buying you an extra few days!

There are four models to choose from with this series, we have the 250, 350, 350e and the 600. They are suitable for tanks between 40 and 160 gallon. The 350e has the amazing ability to be controlled by your PC.

The in hose (the one that sucks water from the tank) is rather large. It could easily suck up your smaller fish. To stop this you can use the PreFilter. It is quite a big grill but you could easily hide it with aquarium plants.

At least your fish will be safe.

The Eheim Pro 4+ Canister filter is a durable and very quiet filter. It is designed to fit neatly into most aquarium cabinets. It is an easy filter to set up and maintaining it is a breeze too.

Here is a video on how to set up this filter:

The Cobalt Aquatics EXT Canister Filter De-Mystified!

Cobalt Aquatics is another canister filter brand that has brought us an awesome canister filter. The Cobalt Aquatics EXT canister filter is for aquariums up to 50 gallons. In my experience, however, it tends to get a bit sluggish past 30 gallons.

This filter is super silent and a breeze to set up. It comes with everything you need to get it up and running in no time at all.

Cobalt Aquatics EXT Canister Filter

It has decent flow rates and can filter a 50-gallon aquarium up to 4 times an hour. This is why I recommend that it is better on a 30-gallon because at 210 gallons per hour you could filter the tank 7 times. Much better than 4 times!

Inside the canister, you have four media trays that you can pack with the filter media of your choice but it does come prefilled. You just need to remove the packaging. Cobalt has designed the canister so that it doesn’t matter what direction the trays go in. Well, as long as they are facing up!

The actual media you get is filter floss, foam, rings, and carbon.

If you have small fish or fry then you will have to add a sponge or something to the end of the in hose. You don’t want to suck any fish up into the filter. If you add a sponge this adds more surface area and that means better filtration.

One problem I have seen with this canister filter is when it comes to priming it. Some customers have reported the water spitting back up in their face due to air in the canister. To combat this I would suggest that you fill the canister with dechlorinated water. This will remove the air that was causing the spraying. Thus making priming a lot easier. In the video below I show you a method to make the filter prime itself – no more wet face!

If budget is an issue then this is the perfect filter for your aquarium. It doesn’t compare with the FX6 by Fluval or the Eheim Pro4+ but it is a good filter for smaller tanks.

Here is an awesome video that shows you the easiest method to set up the filter. No struggling with tubes or priming with this method…

API Filstar XP XL Canister Filter: Most Underrated and Overlooked

Next, on the list, we have the API Filstar XP XL Canister Filter. This filter is sometimes referred to as the Rena Filstar, just clearing that up so you don’t get confused. In my opinion an underrated and overlooked filter choice.API Filstar XP Canister Filter

It does a great job, so really don’t understand why it gets overlooked.

With the L version of this canister filter, you get a filter that is made from a very durable plastic making it extremely sturdy. The filter’s flow rate is capable of 465 gallons per hour so can handle tanks up to 265 gallons. The filter itself will hold 3 gallons of water and runs at 31 watts of power.

When you open the box you have everything you need to get it set up from plumbing to media. Setting it up is so easy, so if this is your first canister you are in good hands.

Inside the canister, you have 4 filter media trays for you to pack with the media of your choice. When your filter arrives you have media to get you started. You will get two foam pads at 20ppi and 30ppi. This is the mechanical filtration.

For the biological you have the premium Bio-Chem Start and for chemical Bio-Chem Zorb. The Zorb is the activated carbon. The baskets should fit easy and snuggly if it doesn’t feel right then re-align the baskets.

The inlet ports are color coded making it easy to know which one is the in and which is the out.

Once you have plumbed the filter and remove all packaging from the media you are pretty good to go as this is a self-priming filter. Here is a quick video on how to set the filter up…

The Eheim Ecco Pro Canister Filter: The Green Filter

If you are looking for an energy efficient canister filter that can get the job done then this one is for you. Let me introduce the Eheim Ecco Pro Canister filter. I know another Eheim filter. That has to mean something for this brand as they always make it onto the best filter lists.

So how energy efficient is the Ecco Pro?

Well, the large version of this filter only runs on 8 Watts of power. Are the rates affected?

EHEIM Ecco Pro External Canister Filter

For the large model, you can expect flow rates of 130 gallons per hour. This is perfect for tanks up to 80 gallons!

Inside the canister, you have a pre-filter ring with coarse foam this will keep the maintenance low for this filter. You only have three trays but they hold a huge amount of media. With most Eheim filters you will get media that you can use straight away and the Ecco Pro is no different. For mechanical you have coarse and fine filter pads. For biological you have the famous Eheim Substratpro. If carbons your thing you also have a carbon pad for chemical filtration.

The impeller blade is made from high-quality ceramic and is super quiet when it is in operation. You can find this in the motor head. Eheim may be pricier than some others on this list but the lifespan is normally the best.

Water is sucked in through the pre-filter and trickles down the side of the canister. From there the water is sucked up through the media to give you that clear water we desire!

Like most Eheim filter you have the double taps to make cleaning an easy job.

Once you have set the actual filter up you just have to adjust the handle and voila your canister filter is primed. Pretty cool if you ask me.

Why Should You Choose A Canister Filter For Your Aquarium Filtration?

Now that you know what is out there let’s take a deep dive into canister filters. The big question is why should you choose a canister filter for your aquarium? Hang on back filters tend to do a good job of keeping the tank in tip-top shape.

Personally, I would be starting to consider a canister filter when your tank is bigger than 40-gallons. In my opinion, they just do a much better job. They are bigger which means a lot more filter media but they can also be hidden out the road which is great for your aquariums aesthetics.

In this section, I am going to share with you the reasons why a canister filter should be your next upgrade for your tanks filtration system.

A Canister Filter Allows A Customizable Filtration System

When you make the change to a canister filter you will most likely be blessed with some filter media that the manufacturer recommends. They will also give you a filtration set up that they believe is best. The way you arrange your media will determine how well the filter actually filters your tank.

With some filters, I have realized their arrangement recommendation is not the best choice. For Example, the Eheim brand normally recommends that you put the mechanical filter pads at the top of the canister in the first tray. This would be ok if the water flowed down.

With most Eheim models the water goes down the side of the media. From there it is sucked up through the media. If you follow their recommended setup the mechanical filtration would be the last type of filtration.

I think that mechanical should be first. From most reviews, I have read people always tend to rearrange the media so that the water goes through the mechanical filtration first.

With a canister filter, you can design the perfect filtration system for your aquarium.

Holds Large Amount Of Filter Media

Like I mentioned above most canister filters normally come with media but this might not suit your own preference. With this type of filter, the choice is yours.

If you have media in another tank that you want to use then go for it. This is actually a good idea as it will cut down the amount of time to cycle the tank before you add fish.

Read More: Learn How To Cycle Your Tank The Easy Way

If you are new to the hobby I would stick with the recommendations that you get. Most brands want you to buy their media so they supply decent stuff.

At least you know, however, that the option is there if you want to swap it for another brand or type of media. It may actually be a good idea to try out some and see which you like best.

Most brands supply activated carbon but I have seen a surge of aquarium owners changing this to Purigen for chemical filtration.

You Can Hide Them Out The Road

Canister filters normally sit outside the tank and are sometimes referred to as an external filter. This is great for your tanks aesthetics but it also increases the amount of swim space for your fish.

More space to swim, happier fish!

Having said this some models like the Cobalt Aquatics EXT Canister filter have a pump that can sit in the tank or out. The choice is normally yours when it comes to keeping in the tank or out of the tank.

If you have an aquarium cabinet then most canister filters will fit in these with no issues. The brands tend to design their cabinets to suit most canisters. This means that all the tubes and the canister are hidden away from viewers.

Adjustable Flow

As well as customizing the type of media and the way the filter actually filters the tank, you can also adjust the flow too. This may be to increase the comfort of the fish or to reduce surface agitation.

With some models, you can make the filter bypass parts of the filtration buying you some time when maintenance is due. For example, with the Eheim Pro 4+ you can hit the Range Extender and the filter will bypass the fine media, buying you some extra time.

You can set up your hoses to create more surface agitation or less.

If you find that the flow is pushing the fish and tank decor around you can reduce the flow rate on some models. If your filter doesn’t have the option you can maneuver the out hose to get a better flow like in this video:

Quieter Filtration System

With a lot of the top quality hang on backs you will probably get yourself a pretty decent filter when referring to noise. Nobody wants to listen to the buzzing of a filter motor.

With HOB’s you tend to hear water trickling but is that really such a bad thing.

I find it quite relaxing in fact!

With a canister, the manufacturers are striving for that quieter filter and in my opinion, they are quieter in comparison. What you must remember is that most fish keepers will keep their canister filters out of sight in a cabinet.

So now a filter that is already quieter has a cabinet that the noise has to get through too.

With a canister, depending on your flow, you may still hear the water trickling. If it bugs you then you can easily change the position of the spray bar or spill tip.

Easy Maintenance

The last big selling point for me is the ease of maintenance. You will no longer have to mess with trying to empty the water from a hang on back filter.

The canister has a plumbing system that connects to your canister. This means you just have to disconnect the canister from the plumbing. With some models like the Eheim Range, they even have a double tap to turn off the flow.

All you have to do is remove the hoses and the motorhead from the canister. Once disconnected simply take your canister to the tub or the kitchen sink to clean it.

Once you are done, connect the hoses and motorhead back to the canister and you are ready to prime and go once again.

How to Choose A Kickass Canister Filter For Your Aquarium?

When it comes to picking a good canister filter for your tank you are blessed with hundreds of choices. Fluval, Eheim, SunSun, Hydor, API etc…

The question is… which one is the best fish tank filter?

The best filter for your aquarium is the one that can filter all the water in your tank at 4 times per hour. Now, this will depend on the fish you keep inside your tank and also if you keep live plants.

If you keep goldfish I would recommend that you get two filters so that they can cycle your tank up to ten times in an hour. Goldfish are heavy waste producers. For more information check out my article: Do Goldfish Need A Filter?

For most fish, though, four times an hour will be fine. If you feel like the tank is cloudy or not up to your clarity standard then you could add another at a later date. You can never over filter your tank!

Let’s move onto the actual physical filter now. The first thing you should check is the clamps. How strong are these? If your clips were to break free you could have up to 3 gallons of water and fish dirt floating around your floor.

This is all you really need a canister filter to do. The actual filtration part is done by the media inside the canister. The actual filter is just moving the water into the filter and back out.

Most filters will come with a pretty good media, especially if you buy from one of the premium brands. If you choose a cheaper make of filter you may want to upgrade your filter media to a premium brand like Eheim or Fluval.

The best way to judge the quality of the media is to try different ones. When you find one you like and one that delivers pristine water… stick with it!

How Exactly Does A Canister Filter Work?

To make it easy for you to pick the greatest canister for your fish tank it is important you actually know what the filter should do. We know that our filter has to be able to run every gallon of water through the filter four times an hour.

But what is the canister actually doing to the water?

You have two hoses, one that draws water into the filter and one that pumps water back into the tank. This is all done via the motorhead.

To help you understand I am going to relate this to an Eheim Classic Filter.

So when the water comes into the canister it is pushed down the sides of the canister. At this stage, it hasn’t gone through the media at all.

Once the water reaches the bottom of the canister it is then sucked up through all of the filter media. The result is clean and fish safe water.

Types of Filtration

To successfully filter your tank, though, your media has to have at least 2 types of media. A mechanical type and a biological type.

These will help get rid of debris but the biological media is also home to the good bacteria in your tank. That good bacteria will live on the biological filtration and will help change ammonia to nitrites and then nitrites to nitrates.

Ammonia and Nitrites are very dangerous to fish. In fact, these are the biggest killers when it comes to new fish keepers. These bad bacteria come from fish waste so it is important that the good bacteria can change those nitrites to nitrates.

You may have heard of chemical filtration. If you add Purigen or activated carbon to your filter media you are adding a chemical stage. This will help remove any impurities or pollutants that the biological and mechanical media can’t handle.

Canister VS HOB: Is A Canister Filter Really Better Than A Hang On Back Filter?

When it comes to making your mind up between a canister filter and a hang on back filter the size of your tank is the big decider. Most hang on backs are designed for smaller aquariums, whereas canister filters are designed to filter large amounts of water.

Some canisters hold 3 gallons of water inside them when not flowing. This is a lot bigger than the smaller hang on backs(HOB)!


One of the main differences between the two is the cost. You can normally get a decent HOB filter like the Aquaclear 110 for around $50-$100. For a decent canister filter, the prices are going to start around $100 and can go all the way up to $500 or more.


Being attached to the tank lends itself some disadvantages too. Aesthetics for example. If your filter hangs on the back then your tank may have to be away from the wall to allow space for the HOB. With a canister, you can run the intake and outtake hoses from the tank to a canister which is stored in a cabinet below the aquarium.


Look at the sheer size of a canister filter. Inside that canister is mainly filter media. This is a lot more surface area for good bacteria to colonize. It holds a lot more media too. With a HOB you might have to use cartridges or only be able to add a small amount of filter media.

Ease Of Use

A canister filter looks pretty intimidating with their hoses and strange little elbow pipes. You have to know how to put all this together. This is pretty easy if you follow instruction. With a HOB you just hang it and turn it on.

No plumbing or priming!


The Aquaclear range is the quietest HOB’s I have encountered but I still think that a canister filter is a hundred times quieter. With most HOB’s noise will be more noticeable. Canister filters tend to be quieter and you can hide them in a cabinet reducing the noise further.


On the whole, a canister is a lot more customizable. You can have the intake hose at one end of the tank and the out hose at the other side. This provides a more adequate flow of water in the tank.

With a HOB you are limited, it sits where you install it and then sucks water in and straight back out again in the one area.


HOB’s are very reliable and so are canister filters but there is always that 1% chance that something could go wrong. If your HOB leaks which is very unlikely you will not have as much mess to clean up.

A canister on the other hand, could leak up to 3 gallons of water on your floor.

Canisters are pretty reliable and good filter maintenance will improve their lifespan. In my opinion, a canister filter beats a hang on back filter hands down.

How To Set Up A Canister Filter For Successful Filtration

Canister filters may look intimidating but once they are setup you do not have to dismantle much. In this mini tutorial, I am going to show you how to set up a Fluval FX6 Canister filter. Most canister filters are set up in a similar fashion.

Step One: Remove Packaging

Take everything out of the box and remove any packaging from the physical parts of the filter. When you unbox you normally will find the actual canister in a bag. The filter media will be inside the canister but will also be inside some packaging. Never forget this!

Always check the canister for extra packaging.

Step Two: Setup Media

Next, we are going to set up the filter media. This will depend on your own personal choice. For me, I would always choose to put our chemical filtration first like in the video above.

When you are putting the second tray on top make sure the ends line up because that is where the intake and outtakes will go.

In the second tray, I would add the bio disks. These will only come halfway but you can always have more.

On the third tray add your mechanical filter pads.

I actually prefer the mechanical tray to be before the biological to stop the debris getting into our biological filtration. This may clog it up!

Install the handles, these just clip in to place.

Step Three: Add Trays To The Canister

When you put the trays in the canister you need to make sure that gaps for the hoses line up with the baskets. This means the filter can only be set up in one way. This makes your life easier and reduces any risks of leakages.

Step Three: Line Up The Trays

The input hose on the top makes it super easy to replace the lid. It can only go on one way!

Pull up all the clamps but do not tighten as we are going to fill with water before you tighten the clamps.

Step Four: Hooking Up To The Tank

When it is time to hook up the filter to the tank the first job is to install the valves and input grill to the input hose. If you find it is tough you can stick the hose in boiling water for a few minutes and this will make it easier to attach everything to the hoses.

Next measure the distance between the filter and the fish tank and cut the amount of hose needed. It is better to be generous here. You only get one shot and you want the filter to be manoeuvrable. If you cut to short you may have to get yourself some more hose from the fish shop.

When it comes to installing to the tank you need to make sure that the filter sits below the aquarium or at least 8 inches below the water line. This is a gravity fed system so it won’t work above this. Attach the hose to the clips in the tank like in the picture below.

Fluval clips to hold hoses on the tank

Next, do the same for the output. Attach the valves and then attach to tank.

I advise that you put the in on one side and the out on the other side for better water flow. If you have bubblers in the tank keep the input hose at the opposite end. The biggest problem new fish keepers face is getting air in the canister.

Once both are attached to tank you can go and attach to the actual canister motorhead. Make sure the right hose connects to the right valve on the filter!

Step Five: Plug in & Let It Run

Now that your filter is hooked up to the tank it is time to plug it in and let it run. This initial stage is all about getting water into the filter. You might want to add some in before you switch on.

Now the neat thing with the Fluval FX6 is that it has a circuit board inside that is constantly monitoring the performance of the filter. Every 12 hours this is going to shut off and reboot. This is just to improve the performance of the circuit.

When you first switch on it will fill the canister with the amount of water needed and then switch off. Then you will see bubbles getting spit out. That is the system purging your filter of air.

Pretty neat feature in my eyes as air can cause problems for your new canister filter.

Maintaining A Canister Filter To Keep Your Tank In Tip Top Condition

Once you have been running your canister filter for a while you will have to do some maintenance to keep it performing at it’s best. If you never maintain it, the aquarium will get murky as all the debris is just sitting in the filter. The good thing is these filters can go for a long time before they need any attention.

You need to leave enough time for the good bacteria to do its job. For most filters, I would suggest about 6-8 weeks. That’s like two months before you have to. Very low maintenance in my eyes.

With this type of filter, the job of cleaning and maintaining is a breeze. First things first… turn the filter off.

Now it will vary from model to model but the idea is the same. First, remove the motorhead.

For the media rinse with siphoned aquarium water to keep the bacteria good.

Once everything is rinsed. Simply put everything back together and your good to go. Check the seal for any grit to help prevent leaks. Once you are sure that there is no grit, attach the clamps and then open the valves to refill the canister.

Tank maintainance… Done!

In Summary: What Really Is The Best Canister Filter For My Tank?

Wow… That is us done!

As you can see there is a lot to learn about canister filters but it really isn’t that hard. When you choose to make the switch and have your first canister in front of you it will all come together.

The brands I mentioned are the ones that I recommend but there are loads out there. If budget is a big deciding factor you may want to go for a cheaper brand and get a more premium filter media.

If you really want to do the best by your fish I would suggest spending the money on the filter. You really do get what you pay for.

If it was me I would choose the FX6 by Fluval. I just think the amount of research they do really does show in their products. In my experience, their customer support has been first class. I  have heard others say differently but for me, they have been great.

The FX6 is an easy to use, a durable and quiet filter that you can easily get up and running in within an hour.

It is low maintenance leaving you more time to enjoy the actual fish tank.

The choice is yours. If you have any questions feel free to leave a comment and I will do my best to get back to you as soon as possible. I really do hope this article has helped you pick the best canister filter for your aquarium.

ImageNameAquariumsRatingCustomer Reviews
Fluval Canister Filter, FX6 FilterFluval Canister Filter, FX6 FilterSaltwater or Freshwater up to 400 GallonSuccessful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
EHEIM Classic External Canister FilterEHEIM Classic External Canister FilterSaltwater or Freshwater up to 90 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Hydor Professional External Canister FilterHydor Professional External Canister FilterSaltwater or Freshwater up to 150 GallonSuccessful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
Marineland Magniflow Canister FilterMarineland Magniflow Canister FilterFresh & Saltwater up to 100 GallonsSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Penn Plax Cascade Canister Aquarium FilterPenn Plax Cascade Canister Aquarium FilterSaltwater or Freshwater up to 200 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
SunSun Hw304B 525GPH Pro Canister FilterSunSun Hw304B 525GPH Pro Canister FilterSaltwater or Freshwater up to 150 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Eheim Pro 4 Canister FilterEheim Pro 4 Canister Filter
Saltwater or Freshwater up to 160 GallonSuccessful Aquarium give this tank 4 out of 5 starsCheck It Out!
Cobalt Aquatics EXT Canister FilterCobalt Aquatics EXT Canister Filter
Salt or Freshwater up to 55 Gallon Successful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
API Filstar XP Canister FilterAPI Filstar XP Canister FilterSalt or Freshwater Safe. For tanks up to 265 GallonSuccessful Aquarium give this tank 4.5 out of 5 starsCheck It Out!
EHEIM Ecco Pro External Canister FilterEHEIM Ecco Pro External Canister FilterSaltwater or Freshwater up to 80 GallonSuccessful Aquarium give this tank 3.5 out of 5 starsCheck It Out!
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