In this guide, I’ll explain why I think canister filters are ideal for 20 gallon tanks, and then review the top 4 and tell you which is the best canister filter for 20 gallon aquariums.
Quick Overview: Top Pick
After review the top choices, and based on my personal experience, the Fluval 107 is the best canister filter for 20 gallon tanks.
Last update on 2023-12-01 / Commissions Earned / Images from Amazon Product Advertising API
Why I Think Canister Filters Are Best for 20 Gallon Tanks
More Biomedia
One of the best things about a canister filter is that there is a ton of room that can be packed with biomedia.
Most hang-on-the-back filters have really limited space for filter media, especially ones that are meant to use cartridges. It’s just a matter of fact because of the overall design.
But canisters have huge compartments that can hold five or ten times as much filter media.
Increased Flow
You can really increase the water flow in your tank using a canister filter.
Water is sucked into the filter through the intake hose and then pumped back into the tank through the outflow hose.
If you put the outflow on one end of the tank, and the intake on the other end, it will create a current that runs throughout the whole tank.
Higher GPH
The pumps on canister filters tend to be more powerful, and therefore, they can move more water (measured in GPH, gallons per hour).
This increased water movement is great since it continuously pumps water through the biomedia so beneficial bacteria can remove harmful substances.
Easier to Hide
I like that even though canister filters are much larger than hang-on-the-backs, the body of the filter can be kept in the aquarium stand.
An equivalent hang-on-the-back would be a huge thing on the outside of the tank that’s impossible to hide.
20 Gallon Canister Filters Reviewed
1. Fluval 107 Performance Canister Filter (Top Pick)
Key Features:
- GPH: 145
- Quick release hoses
- All trays removed at once
- Vertical mechanical filtration
- Mechanical, chemical and biomedia included
- Easy priming handle
- Super quiet motor:
The Fluval 107 really is a top-notch filter. It’s got a lot of unique design features that set it apart from other filters on the market.
On most canisters, the mechanical media sits in one of the media trays. But the 107 has big sponges that sit vertically inside the canister.
This filter also comes with all of the filter media that you need to get started.
My one nitpicky thing is that it doesn’t come with a spray bar. You can buy one separately, but I don’t think that should be necessary.
Pros:
- Quick release hoses make maintenance easier
- Includes all the filter media you need
- Easy to remove media baskets
Cons:
- No spray bar
Last update on 2023-12-01 / Commissions Earned / Images from Amazon Product Advertising API
2. Penn Plax Cascade Canister Filter
Key Features:
- GPH: 115
- Quick release hose
- Flow valves can rotate 360
- Transparent filter body
- Mechanical and chemical filter media included
The quick release hoses let you quickly disconnect hoses and keep water from draining out of the tank.
The flow valves (where the hoses connect) can rotate 360° so they can more easily fit under the tank stand.
I also think it’s really cool that the body of the canister is transparent. So you can actually see that it’s filling up with water once you’ve got it primed.
This filter comes with mechanical filter media and activated carbon, but it does not include any sort of biomedia. I’m not thrilled about that.
Pros:
- Easy to place under tank stand
- Rotating flow valves fit under any cabinet
- Includes some filter media
Cons:
- No biomedia included
Last update on 2023-12-01 / Commissions Earned / Images from Amazon Product Advertising API
3. Marineland Magniflow 160 Canister Filter
Key Features:
- GPH: 160
- Mechanical, chemical and biomedia included
- Canister lid clamps are identical
- Quick release hoses
The Marineland 160 is a great all round canister filter.
I really like the design of the quick release for the hoses. It’s so easy to detach the hoses when you need to clean but it’s also very secure because of the way it locks down.
Another nifty feature, the clamps on the canister lid are all the same. So the lid can be oriented any way you want.
This is really handy when you’re putting the canister back together because you don’t have to figure out which way to turn the lid, it will go on no matter which way you turn it.
The canister also comes with mechanical, chemical and biomedia. I personally would replace the plastic bio balls with ceramic biomedia, but otherwise, you’re good to go.
Pros:
- All filter media included
- Quick release hoses
- Easy lid installation
Cons:
- You may want to replace bio balls
Last update on 2023-12-01 / Commissions Earned / Images from Amazon Product Advertising API
4. EHEIM Classic 150
Key Features:
- GPH: 116
- Open canister with no trays
- Includes mechanical and biomedia
The Eheim Classic 250 is probably the simplest of all the filters on this list.
The media inside the canister does not sit inside trays. Instead, it’s loose inside the canister. I find this to be a pro and a con at the same time.
I like it because it should cut down on water just going around the tray instead of flowing through the media.
But, with no trays, there’s no handy way to get the media back out of the filter for cleaning. So you’ve got to scoop out gunk covered media with your hands.
Not my idea of fun.
Also, there’s no priming button or lever. When you want to prime the filter after maintenance, you have to disconnect the outflow and suck on the hose to get water to start filling the canister.
But, Eheim is another German manufacturer, like Fluval, known for the reliability of their products. So, if you’re willing to skip the bells and whistles of other filters, this Eheim should last you for years and for a really economical price.
Pros:
- Simple design
- Reputation of reliability
- Economical
Cons:
- Maintenance is a bit more difficult
- No media trays
- No priming button
Last update on 2023-12-01 / Commissions Earned / Images from Amazon Product Advertising API
Which One is Best?
There are a lot of great filters on this list.
But, if I had to pick one over the others, I’d have to go with the Fluval 107. I really like that you can take all of the trays out at once and I think the vertical mechanical media is a great innovation.
I also have had tons of personal experience with Fluval products and I have a lot of faith in their reliability.
Last update on 2023-12-01 / Commissions Earned / Images from Amazon Product Advertising API
