Penn Plax Cascade Marlin Canister Filter Review

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Whether you’re seeking a canister filter for a new aquarium or for your old, reliable one, the Penn Plax Cascade Marlin Canister Filter could be your ideal fit.

It’s easy to set up, simple to maintain, and with the inclusion of the primer button and adjustable flow rate, it’s rather convenient to use.

penn plax marlin canister filter

Unfortunately, not everyone who tried this filter had a good experience. Some testers had issues with the filter leaking, breaking down, or not working as advertised. Are these the rare instances or the overall verdict?

Before you make your final decision, let’s take a closer look at the Penn Plax Cascade Marlin Canister Filter.

Penn Plax Cascade Marlin Canister Filter: The Details


  • Weight: 6 lbs.
  • Dimensions: 13.5 x 10.6 x 8.4 inches.
  • Filter Capacity: Up to 45 gallons.
  • Flow Rate: 172 gph.
  • Media Stages: Three-stage media.
  • Self-Priming or Standard: Self-priming.



The Penn Plax Cascade Marlin Canister Filter works on aquariums that hold up to 45 gallons of water. Penn Plax does offer bigger options, so don’t be discouraged if you have a larger tank than this.

Since 45 gallons is an averagely sized tank, if you have a fish bowl or a gigantic aquarium, this is not for you.

However, if you own a tank that is around 20 to 45 gallons, the Cascade Marlin will suit your needs perfectly.


In terms of media, this Cascade Marlin filter comes with Bio-Floss to trap particulates and pieces of food.

Along with this, you have Bio-Sponges for biological filtration, but Penn Plax also recommends getting Pro-Carb/Pro-Carb-Z, which is filled with activated carbon.

Finally, there are Bio-Rings, which allow for better circulation of the water and more oxygen to be transferred into the tubing.

The filter also includes two large media trays to store all of these items. Because they are rather sizable, they’re easy to remove and clean. No juggling required!

Adjustable Flow Rate

This canister filter has an adjustable flow rate. So, while it can work through 172 gallons per hour, that can be adjusted based on your needs.

You can tweak this rate with the flow control handle and the two valve taps, the latter of which can be rotated 360 degrees.

If the water is moving too quickly and your fish are being sucked to the tubing, you can lower it to a more gentle flow.


The Cascade Marlin comes with a UV sterilization light on the filter that helps control a number of things, including algae, bacteria, fungi, and protozoans.

Additionally, it helps prevent the water from turning green and shuts off automatically when the clips on the filter are opened.

However, this only comes with certain filters, so if you buy this on Amazon, make sure to select the correct one.

Primer Button

Priming is one of the most difficult and – at times – the most frustrating parts of buying a new filter. However, this Cascade Marlin removes that hassle with the inclusion of a primer button.

Simply press it a couple of times and the filter is primed. It doesn’t get much easier than that!

Penn Plax Cascade Marlin Canister Filter Review

The Positives

Easy to Set Up

The Penn Plax Cascade Marlin Canister Filter is very easy to set up. It shouldn’t take more than half an hour.

Once all the pieces are unboxed, you will first remove the top and take out the media trays. Fill them up with whatever media you prefer or just use the included media.

Finally, place the filled trays inside the filter, stacking them on top of each other.

Next, put the motorhead on top of the filter, securing each of the four clamps to guarantee it is properly attached. Adjust the inlet and outlet nozzles to your liking, and then adjust the flow rate to best suit your aquarium.

penn plax marlin canister filter

Attach the tubing to the intake and outflow nozzles. They are colored, so it’s easy to figure out which one is which.

Finally, attach the tubes and the filter to your tank, placing it wherever you decide. After this, just press the priming button – multiple times and very quickly – to get the filter going. That’s it! You’ve set up your filter.


Many users noted how convenient this filter is – especially with the adjustable flow rate nozzles.

There’s no need to buy extra equipment – simply adjust the nozzles to reach the flow rate you prefer, customizing the rate to fit with your unique tank and fish. The instructions are easily laid out for users, so you’ll spend less time fumbling with this filter altogether.

The inclusion of the UV sterilization light means you won’t have to worry about algae, bacteria or fungi taking over your aquarium either, leaving your pets happy and you with less to deal with.

What’s even more convenient is that you’ll have your media ready to go right out of the box. While you’ll need to buy replacements later, you can have your filter up and running without having to seek out extras.

Additionally, because this is basically a self-priming pump, there’s no hassle involved in getting things started; it’s just the press of a button!

Easy to Maintain

Testers were also pleased by the easy maintenance involved with this canister filter.

To change the media, just open up the top of the filter, pull out the media trays, throw out the media you want to replace, put in the new media, and place the trays back into the canister.

That’s it. There are no tiny compartments that need cleaning, no difficult parts to disassemble, and no scrubbing required.

If you want to rinse out the trays while you have them outside the filter, feel free to do that as well.

Strong and Efficient

You won’t have to worry about this canister filter keeping up with your aquarium, customers have noted that the Cascade Marlin Filter has a strong flow, ensuring that your filter does its job.

The flow is adjustable, so while it may be too strong for some fish, it will be easy to customize it for them.

Along with a strong flow, you’ll get a quick-acting filter as well. Users loved how efficient this filter is; it won’t take days or weeks before you notice changes in your tank. In fact, most users had their tank clear in a matter of hours or less!

This is great since the filter will show its worth almost immediately, and you won’t have to second-guess if the Cascade Marlin will deliver.

Quiet Functionality

Some aquariums can be annoying due to their sound. Not only does the whirring or gurgling of a filter tend to drown out the welcomed sounds around you, but it can certainly tone down the ‘zen’ depending on where you place it.

You won’t be limited in where you can place your aquarium thanks to how quiet the Cascade Marlin canister filter is though!

Most users noted that this canister filter performs near whisper-quiet so you won’t have to worry about too many interruptions coming from your aquarium.

If you want to watch your fishy friends as you fall asleep, or want the company of your aquarium, you can set your tank and this filter up in a bedroom or conversational area without worry.

The Negatives

Expensive Media

Users were unhappy with how much the media costs. Since these will need replacing semi-frequently, it can impact your budget.

The first batch of media is included, and they are very convenient to use. Nonetheless, when it comes time to swap them out, you’ll be limited to buying the types this filter is compatible with.

The price of Bio-Rings and Bio-Floss can add up very quickly.


A couple of testers had issues with the filter leaking. That’s never good. While the clamps located at the filter’s cap are supposed to make it watertight, that doesn’t seem to be the case.

Some people came home to a great deal of water leaking onto their floors. Due to its low price tag, this may be a “you get what you pay for” situation.

Retired Sooner Than Expected

Some testers also had issues with this Penn Plax filter breaking down after only a month. That is unacceptable.

No matter if a product inexpensive or not, it shouldn’t become defective after four weeks or less. A number of users speculated that, if the filter had been made out of higher quality materials, it may have enjoyed a greater lifespan.

It seems like Penn Plax didn’t put their best foot forward when creating the Cascade Marlin which made a few users skeptical about the brand.

Advertising Issues

There were also a few testers who questioned the Cascade Marlin’s true capacity. Specifically, it didn’t seem to work on 45 gallons at all.

While Penn Plax lists that as the maximum capacity for this filter, many users noted that it struggled to clean anything bigger than a 20-gallon tank.

If you’re looking to use this in a large tank, you’re better off sticking to a smaller aquarium with this filter.

penn plax marlin canister filter

Overall Verdict

After looking through all the positives and negatives, we would cautiously recommend the Penn Plax Cascade Marlin Canister Filter.

A number of users had many problems with this device including leaks, it breaking down, and overall it may not offer the same abilities as those advertised. Luckily, there are many great filters available on the market, so we advise that you continue shopping for your ideal fit.

That being said, if you’re looking for affordability, it may be worth giving this filter a try.

Where to Buy the Penn Plax Cascade Marlin Canister Filter

Penn Plax has a large variety of aquatic equipment and accessories available to pet and aquarium owners. Their products are known for being affordable, and the Cascade Marline Canister Filter is one example of that.

While it’s usually best to check pet, fish, and aquatic stores, Items from the Cascade Marlin line including the Penn Plax Cascade Marlin Canister Filter are available both in-store and online.

You can kick-start your search with the following online retailers.

And of course, you can also find this canister filter on Amazon.

Penn Plax Cascade Marlin review

That’s the end of this Penn Plax Canister Filter review. Willing to give it a try?

Penn Plax Cascade Marlin Canister Filter Rated
  • Build Quality
  • Accessories
  • Design
  • Ease of Use
  • Value for Money

FCG Verdict

While there are some notes to consider when it comes to this canister filter, there are definitely a ton of pros that come with it like its ease of use, and convenient features.

Some components have some users wary, but the Penn Plax Cascade Canister Filter still has efficiency and affordability in its corner.

>>> Check current price on Amazon.

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