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
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.
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:
How to Use HOB Filters.
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.
Capacity: 20 to 35-Gallons
Flow Output: 150 GPH
Dimensions: 6.75 x 7.25 x 4.75 inches
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.
Capacity: Up to 90-Gallons
Flow Output: 400 GPH
Dimensions: 14.2 x 9.2 x 7 inches
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!
3. MarineLand Penguin 350 Power Filter.
Capacity: Up to 20-Gallons
Flow Output: 100 GPH
Dimensions: 8 x 5.5 x 8 inches
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!
4. Tetra Whisper Power Filter.
Capacity: 5 to 10-Gallons
Flow Output: 90 GPH
Dimensions: 4.2 x 6 x 7.1 inches
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.
5. AquaClear Power Filter.
Capacity: Up to 50-Gallons
Flow Output: 200 GPH
Dimensions: 4 x 9 x 8 inches
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!
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.