SunSun 304b Review? vs 404b?

Topic: I’m looking for SunSun 304b reviews because I am thinking of buying one. I want a descent priced canister filter that is going to do a good job on my fish aquarium. Does anyone have a review to share with me on the 304b or maybe the 404b series?


*Awarded Answer
Posted by Alisha H: The SunSun line of canister filters are super popular because of how cheap they are. Some people claim they are “cheap” and not worth it but I disagree. I’ve owned almost every brand of canister filters on the market and SunSun is on of my favorites. I breed fish for a living and highly recommend them. The 304b series is a descent size. I believe that’s one of the smaller ones but they are all good. How can you beat the price when you compare it to a fluval…?! I can run two of them for the price of a single fluval at times.. there are a bunch more reviews found here too.

  • Depends on who you ask. I ordered THREE within two weeks, and each one had an issue. I ended up with the eheim classic 2217and love it. That said, I couldve been extremely unlucky. Many people love the sunsun.
  • I’ve seen few bad reviews, but many of those could have been fake. Happy to see some real reviews 😂 thanks
  • I was trying to save $40, but all the work it took trying them out and packing them back up wasn’t worth it in the end. But again, if money is tight, it might be worth a try.
  • I have a the hw-302 and the hw-402b and they have been great. Well worth the money in my case.

Posted by Nick J: I have the one with the uv sterilizer and I love it! No problems at all and very easy to maintain. The only thing I would say is put it together dry then use the pump to purge the water. I tried to put mine together while full of water one time and my bioballs caused the top rack to float and it was a PAIN to get back together. Other than that one time it has been easy peasy.

  • Ahh that’s so crazy you ask! I’ve been having issues lately it just stopped pumping. But I think the tube section with the skimmer just needed to come off.
  • Have 4 sun sun filters and no issues. Love them!
  • I have just about every type of canister here lol, my favorite would be the Aquamantra, then SunSun, AquaOne, Eheim, Fluval, then a few lower name brands that i cant think of just now. My SunSun has only ever gone down once and that was from a cracked rubber seal, new seal (replaced impeller at same time) and away it went again, i’ve had it 4yrs or so.
  • I have the 504, I wasn’t happy with the xlarge in-tank pump supplied so I replaced it with a 1200 quiet one pump and I’m happy. My next will be the 304 with UV.
  • If you’re looking for good cheap filtration on a budget then you can’t beat them.
  • I have 2, I like them better than my fluvals
  • I have three. I love them. They are so quiet.
  • I love mine. It is sometimes a pain to prime but that might be operator error.
  • Turn it off before waterchange and fill with water when cleaning pads. I never prime my sunsuns I have 5.
  • 99.9% of the time I don’t have an issue. When I break it down to clean it is my biggest issue and sometimes that is because we get the intake and take mixed up.

My 304b is Loud and Noisy

Posted by Maggie Y: I’m not happy with mine.. Installed my new sunsun 704B. And it is so LOUD. I’m extremely disappointed, and it needs to be returned. I did my research, read reviews, asked questions, and it’s just so disappointing. We can hear it all.over the house, downstairs and up, and it’s inside a cabinet. Does your sunsun sound like this??

  • I would return and exchange, like Marc stated, ive had mine for almost 4 months, and its extremely quiet, I have the 304B for my 60 gallon. Cant hear it over the AC from the ducts its so quiet.
  • Make sure the impeller has the rubber tip on both ends. If one is missing look in the spot the shaft goes into. Sometimes it comes off and stays there but it may have fell out. If it’s gone, it will rattle up hell.
  • I was just getting ready to suggest the same thing.
  • I’m very surprised. I have 3 of them and I can’t hear them at all.
  • The noise I hear comes from the top lid, definitely the motor.
    My media includes gravel on bottom, coarse, medium, fine, matrix, ceramic rings (because i had them already), and another layer of fine. I put my ear to the bottom, middle, and top, and most definitely it’s not media rolling around. Definitely from very top lid.
  • Did you purge it out good? Sometimes you have to work at it a bit.
  • Yes, I definitely did that. I tried with my husband a couple times to make sure.
  • One thing that is haunting me. When i opened the box, the little pieces were all sealed in bags. But when i opened the canister itself, there were drops of water. I’m now suspecting that I might have been sent a previously returned product.
  • I tip the unit so the outlet/inlet tubes are on the high side and pump the primer while the unit is running. That helps to drive out any trapped air.
  • I bought the one with the Ultraviolet sterilizer with no problems so far.
  • All of mine were wet also, I think they do that maybe to keep rubber moist??
  • Not used. They water test them before shipment.
  • That was what I first thought. But then with the noise, i started getting suspicious.
  • By far the most common problem is incomplete purging.
  • Thanks to your tips, I feel good about that. When i tipped it, more air did come out. And I shook it around. When we first started it, there was air in the lines, and that made one sound. This sound to me is different. This sound is a deep vibrating hum.
  • Maybe it is sucking air somewhere? Not highly likely but it is possible. Have you inspected the impeller?
  • So here’s what I’m going to do because I’m fed up. I’m going to go check one more time on all joints, check the impeller, rock it around to make sure no air comes out, etc. I’m doing everything one more time. After that, it’ll have to go back. The question is if I risk getting a replacement or just get something else.
  • I’m also wondering if it makes a difference that this is the 704 instead of the 304 that others have. This one is the new model, from what I’ve read. Maybe it wasn’t a good choice.
  • I read positive and poor reviews of every brand of filter, so I’m willing to give sunsun another try.
    I had really hoped I’d come downstairs to silence, but no….
  • Mine is loud if there’s air inside it. Check your tubes and make sure everything tight, should be quiet if all the air bubbles are gone.


My 304b is Buzzing Sound?

Posted by Julie H: My Sunsun 304b suddenly started to make sort of a buzzing/humming sound. It’s only a couple of months old. Should I unplug it now and give it a good cleaning in the morning? I don’t want it to burn out overnight!

  • What’s the water level in your tank? If the water is evaporating, this could cause the noise. Plus cleaning it wouldn’t be a bad idea. I have the same filter
  • Tank level is normal. I do water changes every three days, it never really gets a chance to evaporate.
  • same here. But mine madness that noise when I need to clean the intake and when the water is low. Water is currently low and I know good and ready for a WC. I’ve been due lol too busy though
  • I’ll clean it out in the morning, but should I unplug it for now? I’m worried about it overworking.
  • Would unplugging it be bad?
  • Yes and no. When you unplug it, you interrupt the flow that it gives to the bacteria in the filter and the oxygen it provides in the tank. Do you have an air stone?
  • Okay, now that I have gotten up and actually investigated, it’s the air pump on that tank that’s making so much noise. I can’t tell if it’s making an unusual amount of noise or if I’m just suddenly noticing it more because I’m super tired lol.
  • Check the Impeller. Mine makes that noise when it gets sand in the impeller.
  • Any changes at all to the setup before it started making that change? any new introductions to the setup?


What Media to Use in SunSun 304b?

Posted by James T: Anyone using the sunsun 304B? if so what media are you using?

  • I use pond matrix and 1 tray of marinepure wrapped in filter floss.
  • I think we have media balls and ceramic pellets. Quilt batting for polishing. And I think we have charcoal somewhere in there too.
  • That’s what i’m on the fence about the charcoal. I’ve always used charcoal but since being with different aquarium groups most say they never use it. they suggest using purigen as a replacement.
  • Purigen is a great replacement for any carbon, I use it and my water is crystal clear!
  • I have one HOB filter that has Bio-Chem Zorb and I love it. If you want to stay away from it I say do it. My zorb tank is immaculate. Please excuse the baby fingerprints and hanitizer. 3 kids you know. Lol!
  • Cermic rings, media balls, filter pads, purigen and some of the little pot scrubbers that I had in the HOB before I replaced it with the canister.
  • Some do come with media. Depends on the merchant.
    I am using Marine Land Bioballs, ceramic, rings, scrubbies, and the replacement pads.