# SunSun 404b and 403b Mini Review



## snorkel2 (Sep 30, 2005)

There has been some questions about the sunsuns and I recent did a new setup with a 404b and a 403b.

First you can't tell from the pic, but the color of these units is light gray, not white. So they actual look pretty good.
They are decently quiet as well, similar in sound to a Hydor pro unit. With the cabinet door closed in a quiet room you can just barely hear them, and I mean a quiet room, no tv and no people talking.

Build quality is pretty good, though I did find a couple of quality control oversights. On the 404b the UV indicator does not light up properly and I have to look right on top of it. It appears the there is something blocking it or the light transmitter
stick thats supposed to be in there is missing. I also accidentally broke the little UV switch cover door on the 403.

The 404b is huge, and a single tray holds a full 2 liters of Seachem Matrix. The one it the pic has 4 liters in the middle two baskets, and 3 coarse blue sponge pads in the bottom and 3 white pads in the top.
The 403, has 3 trays and this one has 3 blue sponges in the bottom, 3 boxes of ceramic rings in the middle and 3 white pads in the top.

I also used the plumbing it came with and it has improved over the years, about 5 years ago it was so brittle it would easily break, not so anymore.

I always put any canister filter in a tub as a mis aligned gasket or o ring even on a eheim can cause a leak Eventually I will put a couple of those water alarms in each tub.

The price for these is really decent as well, I got both of these for less than the price of a Hydor 350 canister filter.

See the attached pic link for a size comparison:


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## snorkel2 (Sep 30, 2005)

oh, forgot to mention these are on a 75 gallon tank, the 404b output is being fed to a 3 foot spray bar as the flow from the 404b is really strong, not 500+ gallons per hour, but very strong. The 403 is outputting to a short section of spray bar positioned vertically in the tank.


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## snorkel2 (Sep 30, 2005)

One more thing I forgot, is the 404b is much more difficult to prime without the bucket being filled, I am guessing it's because the 404 has big 3/4 inch hoses, the 403 has 5/8 hoses.
All intake plumbing should have a priming plug, so the hose can be filled with water, which makes priming a snap. Also for cleaning etc these will auto prime no problem as long as you don't drain the intake hose Just put the valve block in, and lock it down and it will fill up, just like a rena XP etc.


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## snorkel2 (Sep 30, 2005)

The other think I noticed is the UV indicator on the 404 is so dim, you can't see it unless you look directly down at it. There seems to be a design difference in the UV quartz sleeve compared to the 403.
The 404 has a metal ring around the top of the socket that blocks any light getting to the indicator tube and the end of the sleeve has a black plastic area that blocks it from the side. Only solution to get the indicator to work would be to notch the 
ring with out cutting all the way through, this would allow some of the light to reach the indicator tube.


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## snorkel2 (Sep 30, 2005)

I went to one of our LFS here in the Milwaukee area (one of the biggest in the southeast wisc region actually) and they had a whole section of display tanks running about 8 of the Aquatop branded SunSun 304b models.


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## Pdxmonkeyboy (Oct 17, 2016)

I have a total of 5 sunsuns. three of the bigger ones, two of the smaller. I have not had any problems at all with them. They are quiet, powerful, hold lots of media and are cheap! I have found that the best way to prime them when they are bone dry is to press the plunger down and then HOLD it down. It will keep filling as long as the plunger is held down.


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## snorkel2 (Sep 30, 2005)

I will try that next time. I am going to make some new intakes with a priming port at the top as well. That is by far the easiest way to prime them, just unscrew the priming cap, fill the hose up, screw the cap back on and then open the valve block on the filter. Works every time and no pumping the primer at all. I will post a guide on how I build these, It's all down with 3/4 inch CPVC and the sunsun intake strainers plug right into the 3/4 CPVC.


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## snorkel2 (Sep 30, 2005)

Well, after 2 weeks I opened up the 403 to add some rox carbon and purigen and I noticed the basket tubes where the UV light goes had noticable degradation I had been running the light since I installed it. The tubes going through the basket in the area of the bulb was not smooth and had a pitted feeling.

This has been reported before about the baskets not liking the UV rays.

My advice is to only use the UV sparingly and rotate the baskets as the lower ones are not affected.

Water is crystal clear so the small amount of plastic particals going into the water does not seem to be affecting anything.

I actually would have got the 404a version which does not have the UV but can't find them anywhere.


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## Pdxmonkeyboy (Oct 17, 2016)

I would love the version you have with the handle on top!!!


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## snorkel2 (Sep 30, 2005)

Have you noticed any tray deterioration from the UV on yours?


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## snorkel2 (Sep 30, 2005)

Just an update on these. They have been running 24x7 for close to a year and I have not had one bit of trouble with them.
The 404b is still very quiet, the 403b has some minor impeller noise, but that might be because I have not cleaned it in a longggggggggg time 
I just cleaned the bigger 404b over the weekend and had no issues, media was dirty so it's not getting huge bypass or anything like that.

After a year running these my recommendation is to get the 304/404/704 size if you have room in your cabinet and the 303/404/703 size for smaller setups. don't even bother with the 302/402/704 size unless for a really small tank like a 20 gallon.

i am actually going to retire the 404 and use a Odyssea cfs 500 for mechanical and fill the 404b completely with bio media.


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## joselepiu (Jul 22, 2017)

can you post pics of your whole setup?...
:fish:   8)  :wink: :thumb: :drooling: opcorn: :drooling: :thumb: :wink:  8)   :fish:


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## BlueSunshine (Jul 13, 2014)

snorkel2 said:


> Just an update on these. They have been running 24x7 for close to a year and I have not had one bit of trouble with them.
> The 404b is still very quiet, the 403b has some minor impeller noise, but that might be because I have not cleaned it in a longggggggggg time
> I just cleaned the bigger 404b over the weekend and had no issues, media was dirty so it's not getting huge bypass or anything like that.
> 
> ...


Thanks for the update, We have been running a 304b for about 3 years with no trouble.

As far as the odyssea cfs 500 goes,we are running 4 of them, it is a beast for mechanical filtration and gives great water flow through the tank. My only suggestion would be to change out the shutoff valves for the ones used on a fluval fx6. After the filter has run for about 6 months the shutoff valve will start leaking when you try to turn it to the closed position. Other than that I have made no other changes and they work great. We've been using them for about three years.


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## snorkel2 (Sep 30, 2005)

joselepiu said:


> can you post pics of your whole setup?...
> :fish:   8)  :wink: :thumb: :drooling: opcorn: :drooling: :thumb: :wink:  8)   :fish:


https://photos.app.goo.gl/LnFyCCQwRhGSefOo2[|/url]


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## snorkel2 (Sep 30, 2005)

So the fx6 aquastop valves work on the cfs500?
That's good to know


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## snorkel2 (Sep 30, 2005)

How loud are your CFS 500s? The one I just got is louder than my sunsun, I think it has a bad impeller or the the pump is bad, vibrates pretty good as well, seller is sending me a replacement pump, the pump it came with had huge suction cups and two overlapped so one side would never stick down. Hopefully the replacement pump works better. Other than that it's a decent filter and has gobs of power and flow. It's to bad fluval doesn't make a smaller sized one.


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## BlueSunshine (Jul 13, 2014)

snorkel2 said:


> So the fx6 aquastop valves work on the cfs500?
> That's good to know


Like they were made for them. LOL


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## BlueSunshine (Jul 13, 2014)

snorkel2 said:


> How loud are your CFS 500s? The one I just got is louder than my sunsun, I think it has a bad impeller or the the pump is bad, vibrates pretty good as well, seller is sending me a replacement pump, the pump it came with had huge suction cups and two overlapped so one side would never stick down. Hopefully the replacement pump works better. Other than that it's a decent filter and has gobs of power and flow. It's to bad fluval doesn't make a smaller sized one.


I find them to be as quiet or a little more quiet than the 304b. The suction cups lap on all of ours but it never concerned me.


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## snorkel2 (Sep 30, 2005)

BlueSunshine said:


> snorkel2 said:
> 
> 
> > How loud are your CFS 500s? The one I just got is louder than my sunsun, I think it has a bad impeller or the the pump is bad, vibrates pretty good as well, seller is sending me a replacement pump, the pump it came with had huge suction cups and two overlapped so one side would never stick down. Hopefully the replacement pump works better. Other than that it's a decent filter and has gobs of power and flow. It's to bad fluval doesn't make a smaller sized one.
> ...


Got the replacement pump installed, it's much less noisy 
While I had it apart I put a media bag with some matrix carbon, should do really well with the high flow.
Also ordes a couple of the fx5/6 valves, thanks for the tip on that.
Did you use the o rings that came with the fluval valves? The ones on the CFS 500 are pretty junky.


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## snorkel2 (Sep 30, 2005)

Just updated to a 704b. 
It's a nice update, the UV has been redesigned and the pump motor is a bit more efficient and it's a bit quieter than the 404b. Output seems to be the same. 
The UV switch is much nicer now and the indicator light can be seen with no mods to the metal part the bulb plugs into.










The Odyssea CFS-500 on the right of the sunsun is now really quiet after I put a OXO Silicon drying mat on the bottom of the bucket and ditched the suction cups and the slide on pump mount.
I tested the pump out of the filter in a laundry tub and it was very quiet so I figured it was vibrating on the bottom of the bucket.


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## snorkel2 (Sep 30, 2005)

ditched the cfs 500 for another 704b. the 704b is the best mode yet of the sunsun, the new UV switch and the quartz tube is much better than all the previous models.
Once you get the air out they are really quiet as well, not as quiet as a eheim but pretty close.


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## snorkel2 (Sep 30, 2005)

One thing I noticed with these filters is if you have bio media in the top tray and don't put a fine pad on top it causes the filter to be 
much louder as the impeller is right above the bio media and causes it to move around and rattle a bit.
I recently set mine up the Pond Guru way with all the mechanical in the bottom tray and 3 full trays of bio (biohome in one filter and pond matrix in the other) 
I noticed the filter was a bit loud, so I put a fine pad in the last tray on top and when it started up it was far less noisy.


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## Deeda (Oct 12, 2012)

Interesting observation regarding the noise level. I wonder if it's because of the water flow causing the media to rattle around?


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## wryan (Dec 6, 2015)

I just picked up a 304b to replace a couple of Marineland Magnums whose motors had died, that I had on a 55G.

I am seriously impressed by how quiet it is ... it's in our living room, sitting out in front of the stand, not in a cabinet, and even with the tv off I can't tell if it's running. Whisper quiet and the flow is impressive.

I used the included 4 white pads in the bottom 2 trays for mechanical and lava rock as bio media in the top two trays.

It's only been running for less than 24 hours so I can't say how it will hold up long term, but it seems to be a really great value for the money (<$80, with shipping)

Appreciate your time and effort on the mini review ... it was what caused me to consider a Sunsun.


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