# New SunSun filter weak flow. Help please



## steven p (Jun 22, 2012)

did you trim up that green tubing? new pipes without 90 degree turns can help too

i have the aquatop 300 and 400uv i think... i was a bit surprised at the flow too.. but it seems to hold steady. when my rena gets dirty, it shows... the smaller of the two aquatops seems to actually require less regular maintenance. i want the bigboy uv unit, the 500 i think. i will probably pick up the sunsun tho, its the same thing but cheaper. it's the size of a small pond filter...

back to filter flow.. ceramic media slowed down mine so much that i threw the stuff out in the yard after a month... sponge and floss for me.


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## Bluek24a4 (Mar 16, 2010)

How long do you have the spray bar? What angle is it pointed at toward the surface?


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## rrastro (Jun 14, 2012)

The angle could make a significant difference.
I have the sunsun 302 and sometimes, especially after I change the filter in any way, my flow is barely detectable. Then I monkey around with the tubing a bit and it usually clears right up. Sometimes there's an air bubble trapped somewhere in the line.


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## Leighkai76 (Jul 19, 2012)

I haven't trimmed the tubing yet. I'm afraid to until I know this thing works right. I'll try messing around with it some to see if that helps. 

I have the spray bar pointed just over the surface and am only using half the bar to help it get a little more flow. I'd like to use the whole thing.


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## OVT (Nov 29, 2011)

I have the same issue with 402B running 40Breeder. The filter also seems to clog up much faster then other filters I've used.

Try removing all media and see if it makes any difference.
Shake the filter slightly to make sure there is no trapped air inside, especially if the filter is noisy.


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## Evilgrin (Oct 2, 2012)

I did notice that the filter does trap a lot of air inside mine was running fairly silent doe over an hour flow was decent but had to move it just to get to something behind the filter that shouldn't have been there in the first place and had a ton of air bubbles come pouring out just as I moved it over, kept tipping it over from side to side and front to back and I was amazed at how much air was trapped in the canister but after fiddling with it for a good 5-10 min I did notice that my flow had improved a good deal, also check the impeller next time your in the filter to make sure it's clean and undamaged.


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## dbthump (Sep 11, 2012)

Leighkai76 said:


> I haven't trimmed the tubing yet. I'm afraid to until I know this thing works right. I'll try messing around with it some to see if that helps.
> 
> I have the spray bar pointed just over the surface and am only using half the bar to help it get a little more flow. I'd like to use the whole thing.


To add to her post, as I am her husband, we cut 1ft off each tube but that doesn't seem to help. 

I guess we're simply wondering if anything is wrong or if that's normal for this type of filter. Switching from noisy top filters to this quiet filter was a bit lack luster. It is filtering but I guess we where expecting it to have tons of pressure. With just one spray bar it might break the surface but with two it's barely moving the surface. I'm worried there won't be enough O2.

Thanks.


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## sbarbee54 (Jan 12, 2012)

I have same issue, been a issue since I bought it. I read online allot of people have this issue with this unit. So I bought other SUNSUN instead of this model and no issue at all


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## RedseaReefer (Aug 21, 2012)

If it filters fine and your just worried about the o2 couldn't your just run an airstone?


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## dbthump (Sep 11, 2012)

Since I did not put this together I decided to back track and found something, epoxy inside the impeller area. I scraped it out as gently as possible and although it did improve flow it still isn't creating as much current as we expected. We're using only one of the two spray bars and I attached a 90* that has a smaller ID, creating a bit more flow. 









As far as we can tell it's doing its job. Compared to the top filters the intake strainer isn't getting covered with junk, so somehow I feel the top mounts where doing a better job because the suction appeared stronger. That said the water only had to travel about 24" and now has to go 5'-6' round trip. If the filtration is better that's all that matters I suppose.

Perhaps we're missing the point a bit. The filter is meant to clean the water. If we want more current we can use powerheads, more O2 use an airstone. Good train of thought? 




RedseaReefer said:


> If it filters fine and your just worried about the o2 couldn't your just run an airstone?


Great point. We've got plants and an airstone if necessary. Reading further I think we'll put the stone on a night timer.

Thanks again.


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## Evilgrin (Oct 2, 2012)

I'm not sure how long you've had the filter running but if it's been a few weeks I'd check the white filter pads since they are "Fine Filtration Pads" they will tend to clog fairly quickly since they are meant to trap fine particles.

One other thing I've found with mine is that it traps an astonishing amount of air in the motor housing I spent a good 10 min tipping mine from side to side and front to back to get most of the air out, I'm thinking this could also slow the flow rate down as well.


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## Leighkai76 (Jul 19, 2012)

If the flow isn't good doesn't that mean the filtering isn't good either? Don't we need a certain amount of GPH?


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## Bluek24a4 (Mar 16, 2010)

So if it makes you guys feel any better, I will tell you my story. On my 55 Gallon, I switched from 4 HOB filters to a SunSun 304B. I wasn't blown away at first by the flow, especially since the 304 is made for a tank bigger than 55G's. Now after having it few a little while, I realize the flow is pretty good, becasuse a HOB is moving water at the surface, while the spray bar is about 5 inches under water. If a fish swims into the spray bar, it will get pushed away. 

When I was setting mine up, it seems like it would have been easy to put way too many 90 degree angle bends on the return going to the spray bar. Try and make sure you have just the one. 

How is the water level in the tank? That will affect the filter. Also, is your spray bar in the water? Or is it at the water level?


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## tr182md (Dec 5, 2011)

First thing I did with mine was get rid of the cheap plastic intake and return. I used PVC and was able to make a much better setup. Drilled some holes in 1/2" tubing with a cap for the intake and used a three way pvc piece for return so it has two 1/2" return at 90 degrees. This works very well. The intake and return that ships with this is not only flimsy but it is much smaller than the tubing creating a big bottleneck to flow.


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## tr182md (Dec 5, 2011)




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## dbthump (Sep 11, 2012)

tr182md said:


> First thing I did with mine was get rid of the cheap plastic intake and return. I used PVC and was able to make a much better setup. Drilled some holes in 1/2" tubing with a cap for the intake and used a three way pvc piece for return so it has two 1/2" return at 90 degrees. This works very well. The intake and return that ships with this is not only flimsy but it is much smaller than the tubing creating a big bottleneck to flow.


I see. So the small diameter intake is affecting the out flow. I'll give that a try. I assume you have the same model?


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## PSiena (Jun 19, 2016)

Just one new point on an old thread for future problem solvers. The quick connect valves can be damaged! They are ball valves, any one of which may be stuck in the closed position even though lever is positioned correctly for open. Remove quick connect assembly and inspect to insure ball valves will align properly to lever position. New assemblies can be had on ebay for about $7.00 if defective.


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