SunSun HW-304 External Filter | Review + Opinions

Characteristics of the SunSun HW-304 Filter

  • Aquariums: up to 560 liters
  • Flow: 2000l/h
  • Filtration: 4 stages of filtration
  • voltage: 55w
  • Weight: 6.3kg
  • Dimensions: 28 x 28 x 43 cm

Like many aquarium owners, we have gone through various filtration systems trying to find the right filter to use in our aquarium.

Many of us have discovered that external filters work better, and people are increasingly talking about SunSun HW 304 external filter, which you can see by clicking here, so a review of the SunSun external filter at could not be missing.

SunSun HW-304 External Filter Review

SunSun HW 304 Reviews

On there are not many opinions, only 7 at the time of writing this review about the SunSun HW-304 canister. The truth is that the overall grade is not bad at all: 3.9 out of five, a remarkable high.

  • Of the reviews left by customers, 50% have rated the Chinese-made device with 5 stars, and 16% with 4 stars. These value positively its magnificent value for money, ease of assembly and cleaning, the great capacity and the low noise it emits.
  • From the critical opinions, the reality is that they complain more about how the product arrived than how it works.

On you can find many reviews, more than 600, and the overall rating is almost the same: 3.8 out of five.

  • 57% have rated this filter with 5 stars, and 12% with 4 stars. They also highlight its value for money, the suction power, the ease of cleaning and its low noise level…
  • Critical opinions complain about poorly written instructions, loss of flow power over time, and various occasional glitches.

Advantages and disadvantages of the SunSun HW-304 filter


  • High capacity and speed
  • Multi-stage filtration with many options to choose the filter media
  • High quality filter media
  • Includes built-in UV sterilizer option
  • Easy to use
  • Silent operation


  • Heavy
  • a bit noisy
  • Few filter media included
  • Does not have flow control at the outlet
  • The instructions are not very helpful.
  • UV sterilization could backfire if left on unattended
  • Self-priming can be disappointing, so starting the filter for the first time can be a bit tedious.

Features of the SunSun HW-304 external filter

SunSun’s HW-304 filter is an aquarium canister filter used to clean dust particles and organic compounds in aquarium water.

Helps prevent unwanted water contamination, algae growth, and keep ammonia and nitrite levels at zero.

But this is also done by all other external filters on the market. So how is the SunSun HW-304 External Filter different?

Construction and design

This filter is somewhat straightforward in terms of appearance. The form is functional but lacks style, and it’s constructed of a flat white plastic that further accentuates the device’s antiseptic feel.

In addition to this, it comes with various accessories that make cleaning much more efficient and precise.

Weighing 6.3kg and measuring 28 x 28 x 43cm in dimensions, it may not be the lightest or most compact filter, but it’s still alright compared to other external filters on the market.

The filter is a bit large, which causes some inconvenience when it’s time to move and clean it. But being an external filter, it can easily be placed on the floor and stored away until it’s time to do so. You can take a look at the filter and its components by clicking here to judge for yourself.

The durability of the device is on par with other models on the market. More robust brands such as Eheim do not have such a significant difference as to disregard the SunSun HW-304 filter. The locking mechanisms are robust and lock on multiple sides to ensure security.

SunSun HW304 Filter Installation

The instructions included with this filter are, simply put, terrible. If you don’t have any experience with canister filters, you may run into some complications.

Luckily, in the digital age, YouTube is your friend. There you will find some good tutorials on how to install the SunSun HW304 filter.

As with other external filters, those hoses can be a bit of a pain at first. However, everything will be easier once you make them more flexible: the hot water method works quite well.

If you like a more professional job, you can get some custom made tubes and thus eliminate the need to work with the stock hoses.

The self-priming feature works quite well and removes one of the main drawbacks of external filters. While you may never need to do any manual priming, if you do need to, just a few pumps of the priming button will have your system ready.


It has 4 baskets to load the filter medium according to the choice of each aquarist. Sunsun includes some cotton filters, bio-ball and ceramic rings with the package, but they are not enough to fill the 4 media baskets. You will need to buy more filter media separately.

  • For the first chamber it is advisable to use foam or synthetic cotton. That will do the mechanical filtration part. In fact, you can use a layer of synthetic cotton on all cameras if you wish. It is a good way to protect the biological filter media from clogging.
  • It uses the second and third layers for biological filtration. Using bio-balls in the second chamber and ceramic rings or lava rocks in the third will give great results.
  • The last chamber can be used for chemical filtration or more biological filtration. If you have a planted tank and you dose fertilizer for the plants then it is advisable to avoid charcoal or activated carbon. Because the carbon will absorb the nutritional elements from the water column.

In a fish tank only activated carbon works to remove odour, water pigmentation and certain medications. The downside is that you have to replace the carbon every three months. Otherwise, it will start to release the absorbed chemical back into the water.

For a plant aquarium you can use Seachem Purigen which works like magic to keep the water crystal clear. And the best thing is that, unlike activated carbon, it is regenerable.

Changing material is no problem, just slide the trays out and place what you need.

SunSun HW-304B UV Filtration

One of the most interesting features of the SunSun filter is the built-in UV sterilizer. Yes, you read well. The SunSun HW-304B model that you can see here, includes a built-in 9w UV sterilizer that guarantees that there are no unwanted microorganisms in the water column.

The addition of a UV filtering light is a definite plus. UV light is well known for its ability to purify water. The UV sterilizer controls the growth of algae spores and bacteria for fresher, safer water. The HW-304B’s 9-watt UV lamp has excellent performance and works well for 2-hour shifts.

That said, there have been complaints that the UV sterilizer is too invasive when left on for too long. But that can be totally avoided if you are a little careful, right?

flow rate

The SunSun HW-304 external filter has quite an impressive flow rate, it is capable of filtering 2000 liters per hour. Compared to the other canister filters, the power of this model is quite impressive.

After loading the trays with filter media, the flow rate decreases to some extent. And over time, the filter media becomes clogged, so the flow rate can drop even further.

To prevent this, the filter media should be washed once a month. Remember, never use tap water to wash the filter media, always tank water for cleaning.

It should be noted that it does not come with a flow control on the outlet nozzle, which can be a bit disappointing. Although you can adjust the direction of the nozzle to get the maximum circulation coverage within your aquarium.

Installed means can also be used to control the flow. Use the amount of material necessary to obtain the desired flow rate.

SunSun HW304 Filter Price

Setting up the device can be a bit tricky, but once you get it, it performs at a level comparable to many more expensive filters.


This part is very easy. Take the filter to the sink and start washing. Be sure to use tank water to rinse the filter media to preserve all the good bacteria that help promote filtration.

Ideally, you want to disassemble the filter into its component parts to leave each part as clean as possible.

Lastly, reconnecting everything when you’re done should be a piece of cake since you’ve already loosened all the hoses and you know the assembly process.


One of the most annoying things about a filtration system is noise, however it is very difficult to find an external filter that does not make noise.

The SunSun HW-304 filter is not the loudest filter, but it does make some noise. This is aggravated if there are leaks or problems with the flow of the hoses, but there is a simple solution if you find yourself in such a situation.

Other features

Like other basket filters, you have the option of using the surface skimmer with the inlet tube, which is very useful for keeping the surface of the water free of dust.

The spray bar is included, and the tubes it uses are of various lengths, so they can be mixed and matched to customize the direction and positioning the way you see fit.

You could face a problem with priming. Unfortunately this filter does not come with the best self priming system. Although they advertise it with the self-priming feature, most of the time it might prove disappointing.

Other alternatives

It’s completely natural that you don’t like this particular filter. So here are some alternatives that are also good and will do the same for your aquarium.

Conclusions about the SunSun HW-304 filter

If you’re looking for a great quality external filter without breaking the bank, the SunSun Canister Filter is a good place to start looking.

There are numerous features that we have seen of this model, which provide various advantages.

We hope you have found all the details and information you were looking for.

Publicaciones relacionadas

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *

Mira también
Botón volver arriba