Best Filter For 30 Gallon Fish Tank Reviewed 2023

In this guide, I’ll explain why a filter is important and what you need to look at, then review 5 of the best options available and pick the best filter for your 30 gallon fish tank.

Quick Overview: Top Pick

The Seachem Tidal 35 is the overall best pick for 30 gallon fish tanks. However, if you want to keep shrimp, you’ll need the AquaClear 30 with a pre-filter sponge.

If you’ll have a large bio-load, it’s hard to look past the Marineland Magniflow.

Last update on 2024-04-25 / Commissions Earned / Images from Amazon Product Advertising API

Why Do You Need an Aquarium Filter?

What makes filters critical in fish keeping is that’s where most of the nitrogen cycle takes place, the key process that makes aquariums possible.

The Nitrogen Cycle

The nitrogen cycle is the natural process that breaks down fish waste in your tank and turns harmful, toxic materials into non-toxic ones.

Let me give you a quick breakdown.

Fish put off waste, urine and feces, into the water around them. 

That waste builds up and starts to decompose. As you can imagine, rotting fish poop gets pretty nasty.

It starts to put off ammonia (NH₃). This is bad news since ammonia is highly toxic.

Left to itself, the poop would just keep gathering, putting out more and more ammonia until the water became poisonous and killed all the fish. 

Luckily, we have the nitrogen cycle on our sides. It’s carried out by several species of beneficial bacteria that live in our aquarium filters and break down harmful wastes.

One kind eats ammonia and turns it into nitrite (NO₂ -1). 

Nitrite is also very toxic, but that’s OK because another kind of bacteria almost instantly eats the nitrite and turns it into something called nitrate (NO₃-).

Nitrate is much less toxic and can be allowed to build up in between water changes. 

Filters are vital to aquariums because that is where the majority of the beneficial bacteria live, constantly pulling toxic compounds from the water and making them safe for fish. 

Pro Tip: For a more in depth explanation of the nitrogen cycle, and how to get it going in your tank, please see this article.

Biomedia

Biomedia is an essential part of your filter, I would actually argue that it’s the most important part. 

It’s the material in your filter that beneficial bacteria live and grow on.

You need millions and millions of bacteria to keep up with all the waste your fish produce. Just a layer along the walls of your filter wouldn’t be nearly enough. 

You need a lot more room than that for bacteria to grow on. 

Biomedia is made out of various kinds of porous materials that have lots of little nooks and crannies that greatly increase the surface area inside your filter, it’s like setting up a high rise  apartment building for bacteria.

People use all sorts of things for biomedia, like sintered glass, unglazed ceramic or plastic balls covered in grooves.

Why I Don’t Really Like Filter Cartridges

I’m not a big fan of filter cartridges and here’s why.

For the most part, a filter cartridge is just a plastic frame that holds some activated carbon sandwiched in between layers of mechanical filter media.

That’s it, no magic elves that come out at night and scour your tank clean.

I also don’t think that the carbon itself is necessary in most established aquariums, so it’s just a wasteful expense. It does not filter out ammonia or nitrite, so it doesn’t contribute to the nitrogen cycle.

And the carbon has to be changed out every 4-6 weeks, so any beneficial bacteria that have grown on the mechanical filter media on the outside gets thrown away when the cartridge is changed out. 

So I avoid filters that use cartridges for the most part.

30 Gallon Aquarium Filters Reviewed

Pro Tip: Hang-on-the-back filters with motors placed inside the tank are known as internal motors. They do not require priming.

An External motor is the reverse and may require priming after maintenance and/or power loss.

1. Seachem Tidal 35 Filter (Best Overall)

Key Features:

• GPH: 130
• Internal motor 
• Surface skimmer

The Seachem Tidal 35 is one of the best filters on the market in my experience. 

There is a large compartment that can be filled with biomedia, mechanical and/or chemical media as you wish. I love that you can mix and match media in this roomy space.

The thing I like the most is that it has an internal motor that rests inside the main part of the aquarium.

This is beneficial in several ways.

First, it means you don’t have to prime this filter, ever. Meaning, you don’t have to fill the back of the filter with water to get the pump to start gaining suction. The pump is already in the water, so it immediately starts sucking in water and fills up the back for you.

I love this because you don’t have to fiddle with the filter a bunch to get it started again after a water change or if the power goes out. 

It will start itself back up every time.

Internal motors are also much quieter than external ones. Always a bonus, especially if the tank is in a smaller room.

I love the overall design of the Seachem Tidal 35, but it does have some drawbacks.

My biggest beef is that it is not shrimp or fry friendly. Because it does not have a lift tube, there is no way to add a sponge pre-filter that will keep shrimp and fry from being sucked into the motor.

Likewise, there is no way to disable the surface skimmer. Shrimp and fry are going to get sucked into the filter from there as well.

This can lead to fry and shrimp getting injured or even killed. So I don’t recommend using this filter for any tank with tiny inhabitants. 

Also, the surface skimmer can suck in foods, like flakes and floating pellets, before fish can eat them.

This deprives the fish of the food and means that uneaten food is left to rot inside the filter, helping to foul your water. 

Pros: 

• Internal motor eliminates priming
• Extremely quiet operation
• Large biomedia chamber

Cons: 

• Not shrimp or fry friendly
• Surface skimmer can be a pain

Last update on 2024-04-25 / Commissions Earned / Images from Amazon Product Advertising API

2. AquaClear 30 Power Filter (Best For Shrimp Tanks)

Key Features:

• GPH: 150
• Large media compartment
• External motor

I have to admit some bias when it comes to this filter, I’m currently running four AquaClear filters on my tanks right now.

I definitely know about the pros and cons of this one.

What I like about this filter is the large media compartment. You can fit A LOT of biomedia in this space. And since I don’t generally run carbon in my tanks, I’ve got even more room. 

The filter comes with a large reusable sponge for mechanical filtration and a large bag of activated carbon, for those so inclined.

It’s also really easy to do maintenance on this model. You can easily access the motor/impeller, there’s a handle for pulling out the media and you can just spray out the housing with a garden hose.

You can also easily add on a sponge pre-filter to make this shrimp and fry safe.

What I don’t like: sometimes, the external motor can be a real pain in the butt. Priming is required to get this motor going. 

And sometimes, the impeller sticks. When this happens, you have to unplug it, dump the water out of the filter, take off the motor and fiddle with the impeller to loosen it up.

This filter is reliable in that I’ve always been able to get them going again, but it can be annoying when you’ve just done four water changes and the impeller wants to be babied before it will start again on two of your tanks.

If the power has gone out, even for only a few minutes, double check this filter to make sure it started back up. Usually priming gets them going again.

Pros: 

• Huge media compartment
• Can easily be made fry/shrimp safe
• Easy maintenance

Cons: 

• External motor won’t start sometimes

Last update on 2024-04-25 / Commissions Earned / Images from Amazon Product Advertising API

3. Fluval C4 Power Filter

Key Features:

• GPH: 153
• External motor
• Upright mechanical filter media
• Easy to remove compartments for various media

Whereas the AquaClear and Seachem filters give you a wide open space you can customize, the Fluval C4 Power Filter is rigidly configured with a compartment for each kind of media. 

How…German.

I like that there are handles or finger grips on each compartment to make it easier to remove them for maintenance.

I really like the C4 filter, but I would modify it a bit. I would fill the tray that is supposed to house the carbon full of some kind of biomedia. 

This filter does have a trickle chamber with biomedia already in it, but frankly, I think it’s a bit too small.

Despite that, I really like the overall design of this filter. I think the different compartments and how they all fit together shows a thoughtfulness when putting this filter together. 

I also have a lot of faith in the quality of most Fluval products. Their German made motors have a well earned reputation for excellence. 

Pros: 

• Large reusable mechanical filtration
• Thoughtfully designed

Cons: 

• Needs more biomedia space

Last update on 2024-04-25 / Commissions Earned / Images from Amazon Product Advertising API

4. Marineland Magniflow Canister Filter (Best For Heavy Bio-Load)

Key Features:

• GPH: 160
• Huge media capacity
• Quick release hoses
• No guess lid installation

Just in case you’re wanting something different than a hang-on-the-back filter, this is a great little canister filter with much more biomedia capacity than anything we’ve looked at so far.

This canister has huge media trays that can hold mechanical, chemical and/or biomedia. Again, for me, I’d load it with tons of biomedia to process fish waste.

Really, the only drawback to this filter is that maintenance on a canister filter, any canister filter, is quite a bit more involved than sprucing up a hang-on-the-back. 

But, Marineland has done a good job of making the media easy to access. 

Also, it doesn’t matter which way you put the lid on. So you don’t have to spend half an hour trying to figure out which side is the front or back. Trust me, very nice.

Pros: 

• Huge media capacity
• Features to make maintenance easier

Cons: 

• A bit more work to maintain canister vs. hang-on-the-back filters

Last update on 2024-04-25 / Commissions Earned / Images from Amazon Product Advertising API

5. MarineLand Magnum Polishing Internal Canister Filter

Key Features:

• GPH: 290
• Internal filter design
• Simple design
• Super easy maintenance
• Dual mechanical filtration

This Marineland Magnum Internal filter is very different from the other models I’ve covered today. 

This is an internal filter, meaning the entire filter housing rests inside the main part of the aquarium.

This has a high GPH for a 30 gallon tank. So it’s better suited to fish species that like a high flow rate, for example, hillstream fish like danios or butterfly loaches.

The internal canister design is extremely simple to set up and maintain. It does not, however, come with any biomedia. So be sure to pick up some extra.

Mechanical filtration from this filter can’t be matched due to its two forms of reusable mechanical media.

The biggest downfall of this filter is that it is a bit of an eyesore in the tank. But, if it’s placed all the way at the back, decor and plants can be placed in front of it.

But, this filter is so quiet and reliable that I really think it makes up for having to hide it a bit.

Pros: 

• Compact but powerful filtration
• Extremely simple to set up and maintain

Cons: 

• A bit of an eyesore

Last update on 2024-04-25 / Commissions Earned / Images from Amazon Product Advertising API

Which One is Best?

Which one is best is really determined by your individual setup.

When it comes to the hang-on-the-backs, I would go with the Seachem Tidal 35 for most applications. I love the internal motor and quiet running.

But, if you’re going to raise shrimp or fry in the tank, I’d recommend going with the AquaClear. You can easily fit on a sponge pre-filter to make it safe for even tiny creatures.

If I was going to be stocking heavily, you can’t beat the media capacity of a canister filter, making the Marineland Magniflow the best choice if your tank will have a heavy bioload.

If I was setting up a river biotope tank, I think the heavy flow that comes from the Marineland Magnum is great. I also like that you can skip priming and enjoy simpler maintenance since it’s an internal filter.

Last update on 2024-04-25 / Commissions Earned / Images from Amazon Product Advertising API