Best HOB Filters in 2021

The humble hang-on back filters known as HOB filters are the most common of all the filtration systems on the market, with a wide range of users. There are probably more variants of this filter than any other kind, which can be confusing to newcomers: How do you choose the right HOB filter for your aquarium?

A Short Look at the Top 5 HOB Filters

Product Features

Penn Plax Cascade HOB FilterPenn-Plax Cascade Hang-on Aquarium Filter 

Capacity: 20 to 35-Gallons
Dimensions: 6.75 x 7.25 x 4.75 inches
Flow Output: 150 GPH
Aqueon QuietFlow LED PRO Aquarium Power Filter

Aqueon QuietFlow LED PRO Aquarium Power Filter

Capacity: Up to 90-Gallons
Dimensions: 14.2 x 9.2 x 7 inches
Flow Output: 400 GPH
Marineland Penguin Power Filter

Marineland Penguin 350 Power Filter

Capacity: Up to 20-Gallons
Dimensions: 8 x 5.5 x 8 inches
Flow Output: 100 GPH
Tetra Whisper Power Filter

Tetra Whisper Power Filter

Capacity: 5 to 10-Gallons
Dimensions: 4.2 x 6 x 7.1 inches
Flow Output: 90 GPH
AquaClear HOB Power Filter

AquaClear Power Filter

Capacity: Up to 50-Gallons
Dimensions: 4 x 9 x 8 inches
Flow Output: 200 GPH

There was a time when fish keepers only had a few filtering options: inexpensive undergravel filters, midrange HOBs, and costly canister systems. When I first started keeping fish, there were only two brands to choose from, and neither HOB offered tanks smaller than 10 gallons or larger than 100 gallons.

HOB Filters: An Overview

There was a time when aquarium filtering choices were limited to a few inexpensive undergravel filters, midrange HOBs, and costly canister systems. When I first started keeping fish, there were only two brands to choose from, and neither HOB was available for tanks smaller than 10 gallons or larger than 100 gallons.

Filter technology has advanced significantly since then, and HOBs are now available in budget and luxury models, as well as for tanks of all sizes. Let’s take a look at the best hang-on back filters and discuss why they’ve become so famous in the last decade!

The Benefits of Hang-On Back Filters.

Before we get into HOB features and how to choose the right one, consider why you will need this form of filter over the other choices. Every style has advantages, but I would argue that the advantages of HOBs make them an excellent choice for a wide range of inexperienced and seasoned aquarists:

  • HOB filters are among the simplest to mount in new or existing tanks.
  • HOB power filters are electrical in nature and do not require a separate air pump to work.
  • They are available in more sizes than any other style, with capacities ranging from 5 to 500 gallons.
  • The HOB architecture makes it possible to access the filter pads, media, and motor/impeller for routine maintenance.
  • They have two or three phases of filtration, and the filter pads/media can be customized to provide the exact form of filtration your tank needs.
  • The best filter style for neighborhood freshwater and saltwater aquariums, cultivated tanks, and reef tanks.
  • Easily used as the main filter or as a secondary filtration system for larger or more complex aquatic setups.

HOB Filter Features.

Penn Plax Cascade HOB Filter

Now that you’ve learned about their advantages, it’s time to discuss the usual HOB features. Although all filters do the same job, HOBs have some special ways of cleaning the water.

Filtration stages allow customization.

The versatile nature of the box that contains the stages of filtration: the filter pads and media, is one benefit of HOBs. While most manufacturers offer pre-filled replacement pads with media that you can simply insert into the filter, you can also save money by purchasing padding in bulk and cutting your own.

HOBs are designed with at least two stages of filtration: mechanical and chemical. Many high-end HOBs often have extra baskets or containers for storing different types of media for targeted chemical filtration. The third stage for biological filtration has also become very popular, though the efficacy of these stages varies.

Impellers and motors.

HOBs have an external motor that is normally attached to the bottom of the filter box’s intake side. The motor inside the box spins an impeller, which pulls water up the intake channel. The magnetic impeller is in direct contact with the water flowing through your filter, but the motor is shielded and remains dry.

One of the most difficult aspects of maintaining a HOB is keeping the impeller clean and clear of algae, sand, and other debris. Since the impeller is just attached to the motor by a magnet, it doesn’t take much buildup to stop it from spinning. If your filter begins to make a grinding noise, you may need to service or repair the impeller.

Since the motor is not located inside the aquarium or filter box, HOBs are usually noisier than internal and canister filters. When the motor is working, you can most definitely hear a buzz, and the state of the impeller will obviously affect the sound. Because of these noise concerns, some aquarists stop using HOBs in bedroom tanks.

Intake and Exit

To suck up debris and pass water through the filtration device, all HOBs have an intake connected to a tube that sits in your tank. The height of the intake may normally be adjusted, but for deep tanks, additional hard plastic tubing can be needed to extend the intake lower.

Intakes usually have a plastic screen to prevent fish from being sucked into the filter, but if you have a lot of delicate fish, shrimp, or fry in your tank, you may need to change this. I often replace the plastic screen that comes with HOBs with a fine sponge filter tip. This, however, has the potential to reduce your flow rates.

The outflow on a HOB is similar to a waterfall function in that it returns filtered water to your tank. This helps to oxygenate your water, but it raises the filter’s noise, particularly when your water level drops. The outflow also causes further evaporation, which can result in hard water deposits and salt creep in marine tanks.

Choosing the proper HOB Filter

If you’ve determined that a HOB is the best option for your tank, how do you go about investigating and selecting a filter? When purchasing aquarium filters, I look for four things:

Fisk Tank Size.

Look for a model that is appropriate for the size of your aquarium. Most filters will have a tank size or range of sizes specified on the box to help you decide, but this can be subjective. It is not a good idea to use a filter designed for a particular tank size, as this can result in your tank being under- or over-filtered.

Flow Rate.

Most manufacturers will list the maximum flow rate or gallons per hour (GPH) cycled through the filter under ideal conditions. The condition of your filter’s intake tip, pads, media, impeller, and the motor will determine your actual flow rate. Flow rates can be reduced or changed by using filled media baskets.

Although the optimal flow rate is debatable, I typically begin with a filter that cycles all of the water in my tank four times an hour, or twice for low-flow species like shrimp, Bettas, and goldfish. Then, as required, I add extra filtration to the tank, particularly in large or planted tanks. Below, I discuss the use of multiple systems.

Noise.

HOBs are typically noisier to run than canisters because their motor is external and they rest on, rather than under, your tank. Since the motor vibrates the entire package, loose parts or lids often rattle, particularly on low-cost models. There’s also the matter of the sound of your impeller and outflow.

It is common for your filter to become noisier as it ages. The pieces are looser, and the movements are more noticeable. Cheaper filters also need impeller replacement to mask the sound and keep the water flowing. If you are sensitive to noise, HOBs may not be the best option for an aquarium in a TV room or bedroom.

Special Features.

Manufacturers often advertise their HOBs as having unique or special features like adjustable flow rates, LED indicator lights for routine maintenance or to alert you that the filter pads need changing, multiple media baskets, and separate biological filtration stages.

The effectiveness of these features vary by model, so I recommend doing research and talking with other users of the filter before picking your HOB. That will help you identify the filters that have features that work the way you need them to and help you avoid those with gimmicks.

How to Use HOB Filters.

HOB Filter

Now that you know how to choose your HOB filter, let’s talk about how to get the most out of your system. Consider the following factors before deciding on a HOB model:

Filter Spare Parts.

HOBs are normally located in the back of the aquarium, as their name suggests. They’re usually very small to fit between your tank and the wall, and they need around an inch of clearance on all sides. They can even fit on the side of your tank, but with your aquarium lights, lids, and hoods in the way, this may not be possible.

It can be difficult to install a HOB on a rimless or custom-built tank. Instead of attempting to jury-rig a HOB filter on a non-standard tank, you’re always better off going for an internal or canister device. However, the majority of these systems can work in a standard-sized rimmed aquarium.

Make sure you can quickly open the filter box no matter where you put your HOB. You don’t want to find out later that you put it anywhere you can’t see or access it. You should clean your filter box and check your filter pads every month, and you should be able to get to it quickly in an emergency.

Why More Than One Filter May Be Necessary

The flow rate of your filter is important, as I mentioned earlier, but no filter, no matter how strong, will be able to pull debris in from all areas of a large tank. Plants and decorations obstruct flow, so a heavily planted or decorated tank, regardless of flow rating, can need additional filtration systems to keep it clean.

In a wide or long tank, the position of your HOB is more important than in a small or tall tank. In a small tank, the intake should be near the center-back section so that debris can be pulled in from both ends. To keep the tank clear, you can need several filters with intakes in many positions along the back.

Filter Pads and Media Replacement

Although you can normally buy replacement pads that are already filled with media, it could be more cost-effective and efficient to cut your own pads and fill the baskets with bulk media. The majority of brands only use a tablespoon or two of media in their premade mats, limiting chemical filtration.

This also allows you to choose a finer filtering pad for greater water-polishing power, but these types clog more quickly and can reduce flow rate. Even, one of the reasons I enjoy HOB filters is the ease with which I can customize their stages!

Product Reviews for the Best Hang On Back Filters.

Since there are so many labels and styles, it’s never simple to narrow down a shortlist of HOB filters to evaluate. Although I believe these are the best examples of the modern HOB, this is by no means a comprehensive list of filters.

Most of these filters come in different sizes, so if the model I reviewed doesn’t suit your tank, see if they make it in a size that does. Since the features can differ depending on the size, you’ll need to do some research.

1.Penn-Plax Cascade Hang-on Aquarium Filter.

Penn Plax Cascade HOB Filter

Capacity: 20 to 35-Gallons
Flow Output: 150 GPH
Dimensions: 6.75 x 7.25 x 4.75 inches

Check Price

The Penn Plax Cascade with Quad filtration might be the right choice for you if you’re looking for a straightforward 3-stage HOB at a low price. This is a simple filter with a few premium features that are worth paying for. Replaceable filter pads and a coarse, permanent pad for biological filtration are held in the broad media box.

The Penn Plax’s outflow is where things start to get interesting. Instead of simply flowing back into your tank, this stage divides the flow to boost water oxygenation and the biological stage’s work. That’s why it’s referred to as a quad filter. This design also promotes evaporation, which can result in the further build-up in your tank.

Penn-Plax Cascade Hang-on Aquarium Filter Pros & Cons
  • A basic three-stage filter with an extra-oxygenating outflow is included.
  • Has a flow rate knob that is easily customizable.
  • A permanent coarse filter pad promotes the growth of beneficial aquarium bacteria while also providing biological filtration.
  • The adjustable flow rate isn’t very accurate, and it doesn’t affect the rate all that much.
  • Since this model lacks a separate media compartment, the amount of media you can store on it is restricted.
  • Evaporation and mineral or salt build-up on your tank and machinery increase as a result of the special outflow.

2. Aqueon QuietFlow LED PRO Aquarium Power Filter.Aqueon QuietFlow LED PRO Aquarium Power Filter

Capacity: Up to 90-Gallons
Flow Output: 400 GPH
Dimensions: 14.2 x 9.2 x 7 inches

Check Price

I couldn’t decide whether to call the Aqueon QuietFlow LED Pro the quietest or the best for beginners. Although this HOB is very quiet, the AquaClear below it is even quieter. Aqueon’s LED indicator light, which flashes when it’s time to adjust the pads or when flow rates drop due to a clogged filter, can also help novices!

This three-stage filter has two bio-holsters that can be removed and a third screen in the oxygen-rich outflow that allows bacteria to expand. Filter cartridges from Aqueon fit inside these holsters, or the pads and media can be customized. It’s also easy to see what’s going on inside the box thanks to the transparent housing!

Aqueon QuietFlow LED PRO Aquarium Power Filter Pros & Cons
  • Three-stage filter with two modes of biological filtration that is quiet and self-priming.
  • You can see inside your filter without opening the lid thanks to the clear plastic housing.
  • When the pads need to be replaced or the flow rate decreases, the LED light indicator alerts you.
  • The flow rate cannot be changed.
  • The impeller seems to need to be replaced on a regular basis.
  • There isn’t much space for extra filter media.

3. MarineLand Penguin 350 Power Filter.

Marineland Penguin Power Filter

Capacity: Up to 20-Gallons
Flow Output: 100 GPH
Dimensions: 8 x 5.5 x 8 inches

Check Price

I highly recommend the 3-stage Marineland Bio-Wheel as the best hang-on back filter for freshwater tanks. The features differ by model, but the one shown here is the standard version, which is the smallest and ideal for tanks ranging from 10 to 20 gallons. It has the proprietary Bio-wheel for biological filtration, of course!

The powerful motor and impeller inside drive your water through a replaceable filter pad with high-quality carbon chips before returning it to your tank through the Bio-wheel. However, you can easily configure the pad and media. The key disadvantage is that Bio-wheels are difficult to sustain and cause excessive evaporation!

MarineLand Penguin 350 Power Filter Pros & Cons
  • For biological filtration, there’s a 3-stage filter with a proprietary Bio-wheel.
  • The two-part lid makes accessing the inside of your filter box easy.
  • For better results, you can use branded replacement pads/media or customize them.
  • These filters are typically noisier than others, and the two-part lid will add to the noise.
  • The Bio-wheel significantly improves evaporation, making it unsuitable for marine tanks or hard water environments.
  • The price of a premium filter is normally higher than that of other ones.

4. Tetra Whisper Power Filter.

Tetra Whisper Power Filter

Capacity: 5 to 10-Gallons
Flow Output: 90 GPH
Dimensions: 4.2 x 6 x 7.1 inches

Check Price

The older and less costly Tetra Whisper is the perfect hob filter for 10-gallon tanks or smaller. However, it should not be confused with the newer Whisper IQ, which has a different style. This straightforward system is relatively quiet, and it includes a three-stage replaceable cartridge with Bio-foam for bacterial growth.

Although the Tetra has a flow rate of 90 GPH, the current it produces is normally mild, and Bettas do not need baffles. This filter isn’t fancy in any way, including the price, which is usually very poor. The Tetra has one drawback: the bacteria are discarded with the filter sheets, so it isn’t exactly a three-stage filter.

Tetra Whisper Power Filter Pros & Cons
  • The filter is simple and inexpensive, making it ideal for small tanks with low bioload.
  • Tetra filter replacement pads and parts are easy to come by.
  • Bettas like the low flow because it’s normal.
  • Since the biological media does not remain in the filter and is discarded with the pads, the filter is not truly three-stage.
  • Vibration and noise are caused by cheap construction, particularly as the filter ages.
  • The flow rate cannot be changed.

5. AquaClear Power Filter.

AquaClear HOB Power Filter

Capacity: Up to 50-Gallons
Flow Output: 200 GPH
Dimensions: 4 x 9 x 8 inches

Check Price

Consider a model from Fluval’s mid-range brand, AquaClear, if you want a Fluval HOB filter but don’t want to pay a premium price. Even though these basic systems are simple, they are the quietest and best filters on the market. With a filter box configuration that allows for endless customization, they provide true 3-stage filtration.

Rather than using a wheel, the AquaClear has a lower layer of filter foam and an upper layer of ceramic rings that house the beneficial bacteria. Filter pads that can be replaced can polish the water and remove fine debris. In between the layers, you can install any media you want to provide the exact form of filtration your tank needs!

AquaClear Power Filter Pros & Cons
  • It’s very quiet and easy to use, and the flow rate can be adjusted.
  • Water does not bypass the media stages because it goes up from the bottom of the filter to the tip.
  • Customize the filter pads and media used to purify the water for a more compact set-up.
  • Internal media baskets are not included, so you can need to put the media in a mash bag.
  • Because of the high flow rate, many aquariums may need a sponge filter tip to avoid fish injury.
  • Sand substrates are not recommended because they can harm the impeller.

Final Thoughts.

As you can see, HOBs are a great choice for both seasoned and beginner fish keepers and are suitable for freshwater and marine tanks of all sizes. They’re simple to set up and maintain, and the most difficult part is generally deciding which model is best for your tank!

With so many sizes, features, and versatility choices, a HOB can benefit nearly any tank. If you’re still undecided about which filter from my list is best for you, consider the following:

  • My overall favorite and best premium filter on the list is the Marineland, but if you want a simple and inexpensive filter, the Tetra or Penn Plax are good options, or the Aqueon if you want a filter with a few more features.
  • The AquaClear isn’t flashy, but it’s the quietest filter on the market and has a solid design that performs like a luxury filter. If you have rough tap water, I would recommend the AquaClear over the Marineland to save time cleaning mineral particles from your tank.
William
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