Sunsun Hw-304b Pro Canister Filter Review 2020

I don’t know how many fish I accidentally suffocated when I was a noob. It hurts when you see them floating in the water and find out that the reason was a bad filter. But not everyone has the big bucks to buy those high tech filters.

Does that mean you don’t get to play with your fish anymore?


Because we have the 304B pro from Sunsun. Here, in the Sunsun 304b canister filter review, we have explained everything about this product: the goods and the bads alike.

So, here is how you will make your money worth it.

Details of the key features of Sunsun HW-304B filter

susun 304B cansiter filter review

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Here, we have separated every critical element in the product so that you don’t have to read the whole article to get the one thing you wanna know about this filter. Simplicity makes this Sunsun 304b review great.

Construction and Design

The SunSun HW 304B is designed as an external filter that fits perfectly with almost every aquarium stand. Unlike other Chinese products, this filter made its name in durability.

On top of that, it was designed to work with several add-ons and attachments to ensure 100% safe and hygienic water output. It stands 17 inches tall, and it is 11 inches wide. Though a weight of 17 pounds might seem a lot, it will not be a big deal as the filter is installed outside the aquarium.


This is where Sunsun gets wild.

You will have five stages in this filter, four of which offer you filtration media baskets, and the fifth one has a UV light spectrum that kills the last of those pathogens.

Now, what can you use as media?

The answer happens to be, every media you can find in the market. The filter itself will come with cotton filters, ceramic rings, and bio balls. However, the amount of media that comes with the filter will not be enough to fill the baskets. Yeah, I know that you don’t need to fill it to the brim, but we recommend to do so.

For people like me, the lack of this media could be a disappointment, but on the bright side, you get to customize your media choice as you like.

We suggest foam or synthetic cotton for the first chamber, which will act as a mechanical filter. In the second and third filtration stage, use biological filtration media like bio-balls, ceramic rings, and crushed lava. You can use chemical filters in the fourth chamber.

Avoid using charcoal or activated carbon in case your tank is planted. I know, coal is the best filter of its kind, but it also absorbs nutrition from the water. Instead, you can use Seachem Purigen for planted aquariums, which makes your water crystal clear while filtering the bad stuff out.

You might also use synthetic cotton with other biological media to prevent them from clogging.

And, this last chambers seals the deal of it being the best filter in its budget. It has a UV sterilizer that leaves no microorganisms in the water output. This is one of the unique features that you don’t get to see every day in a filter of this price.

It is a 9 watt UV sterilizer that deals with all algae spores and bacteria manifestation. If you are an aquarist, then you have to love this.


There are filters that you have to turn off to get a good night’s sleep, and there is the Sunsun HW-304B. You will have to get very close to the filter to listen to its heartbeat.


This aquarium can work with 150 gallons of water circulating 2000 liters or 525 gallons per hour (GPH). This, of course, implies that the filter is meant to work with bigger aquariums.

The price is making more sense now, huh?

Lucky, you.

However, don’t be surprised to know that these measurements are not considering the filtration media, which will decrease the flow rate a bit. But you will not have problems comparing it with other filters as almost all filters don’t consider the media while showing the flow rate. You can clean the media once in a month for better performance. Always clean with tank water. Tap water is not what you want to use.


You don’t have to google about maintenance now and then. The instruction manual is everything that you need. You will have everything from installation to regular maintenance in the guide.

Clean all the parts, especially that five-stage filter once in a month. That will not only guaranty top-notch performance but also increase the service life of the machine. Be extra careful when replacing the filter media.


  • Powerful water flow
  • Large capacity
  • 5 stage water filtration
  • Built-in UV sterilizer light
  • Self-starting pumps
  • Easy to use
  • Long service life
  • Aesthetic looks


  • Installation could be a bit tricky
  • Little heavy

Sunsun 304b Canister Filter Review

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Let’s Watch the Setup Video Review:

Frequently Ask Questions

Here are some common questions that most aquarists ask about the Sunsun HW 304b external canister filter.

Q1- How do I know the UV sterilizer is working?

Ans- You will find a little window next to the power switch that indicates the UV stabilizer activity. You can easily see the light through this window.

Q2- How can I connect the hose to the kit?

Ans- First, unscrew the top screws of the kit and push the hose about ¼ to ½ inches deep and tighten the screw afterward to lock the tubes. If the hose is not getting in, then put it in some hot water. The water should be hot enough to soften the hose. After getting it soft enough, you can easily put it in the kit.

Q3- Do I need to replace filter media?

Ans- No, you don’t need to replace it. Just clean the filter media once in a month to get better results.

Q4- Can I use the filter without the UV sterilizer?

Ans- Yes, you can. The UV is designed to remove microorganisms from the water. Without the sterilizer, you will not notice much difference in the tank. But as you know, an extra penny worth more than nothing.

Q5- What is the Sunsun 304b hose size?

Ans- The hose that comes with the package is about 5 to 6 feet long. But, you should always keep your tank at a moderate height to get decent water flow.


If you have gone through the article, you already know why I am recommending this for your tank. This is the best at its price.

We also mentioned the negative sides we found while doing the SunSun 304b canister filter review. As you have already seen, none of them are a big deal. All in all, you will not regret buying this canister filter.

So go for it.

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