# SunSun HW-404B leaking into head



## flutterbug (Jan 8, 2012)

I have an older HW-304B that I've been running 2.5 years now and it just started doing the same thing you are describing here. I am trying to decide if I should order another or go with something else. However the fact that I can buy 2 SunSuns for less than the cost of all the other options with the same power makes me think I should just stick with the Sunsun even if it means only getting 2.5 years out of it. The more expensive one that looks like the same design offers a 3 year warranty. An extra 6 months isn't worth more than double the money in my book.  I have a feeling that the problem with water in the housing is caused by the UV light. I have read somewhere about how they leak. I can't remember all the details but I do know that where my button for the UV is has some condensation on it and it never did before. I read that it is not water tight and needs to be dried out if water gets in there. Again I can't remember all the details. I wish they had the 525 gph model without the UV light. It is useless for what I would want a UV for anyways. Mine didn't last very long either and I usually kept it off. I am not sue if I am having other problems with mine. The impeller appears to have a little bit of the magnet chipped off on the top and I keep hearing a jumping impeller sound, then after a few times of that it shuts off. I think it is overheating because if i wait a little while it starts back up. Well so far, it just shut off again and I am waiting to see if I can get it running again.


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## Linwood (Jun 19, 2014)

From lack of response it seems like we are in the minority.

I have yet to tear the old one apart, as I have a new theory. I'm wondering if the problem is in the gaskets on the quick connector where it plugs into the filter. I was waiting for next water change (this week I think) to take a better look. I've never replaced them, but if I recall there are o-ring type gaskets there. If they were leaking, there's openings in the case on top that water could fill, and would (again, I think, not tested) overflow out the sides, not out the top.

Which could explain why no matter what I do to the large gasket it would still leak -- it wouldn't be involved.


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## flutterbug (Jan 8, 2012)

Linwood said:


> From lack of response it seems like we are in the minority.
> 
> I have yet to tear the old one apart, as I have a new theory. I'm wondering if the problem is in the gaskets on the quick connector where it plugs into the filter. I was waiting for next water change (this week I think) to take a better look. I've never replaced them, but if I recall there are o-ring type gaskets there. If they were leaking, there's openings in the case on top that water could fill, and would (again, I think, not tested) overflow out the sides, not out the top.
> 
> Which could explain why no matter what I do to the large gasket it would still leak -- it wouldn't be involved.


That is a good theory! I am not sure if you have ever happened across this sight but this is where I ordered my impeller and o-ring from. Something I read there reminded me of your theory. I would have gone crazy with this Sunsun when I first got it if it wasn't for being able to read this website. Aquarium Filtration | Filter Types | Advantages & Disadvantages

```
For "VALUE", I prefer the AAP/SunSun (which is also sold under different names, but many including the SunSun VARY CONSIDERABLY in quality), although these are not necessarily the best canister filters, these are an excellent choice when price is a major consideration.

However I would caution potential SunSun, Grech, Perfect, or similar Canister Filter buyers that there are some flaws in the return and intake piping, and unfortunately almost all retailers of this filter are not aware of this and do not provide the retrofit of this problem.
```
I am trying to decide if I should get another one or something else right now. I like the idea of a sump but I am bot sure if I want to spend the time it will take for me to learn about it and set it up right now.


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## Linwood (Jun 19, 2014)

I had read that some time ago, indeed I bought spare impeller and UV lights from them.

What I can't figure out though is what their retrofit actually entails. My impression is that it relates to the outer connection where the hoses attach (they speak of an elbow). Because mine are under the tank, the 45 degree now on them works nicely; if they had a 90 degree it would be more awkward.

But the description of a vinyl sleeve puzzles me, not sure if that's a change inside. Maybe it is. Maybe someone who bought one there will chime in.

I can't do a sump easily because my tank is not drilled. I know there are some alternatives, but nothing really pretty. And frankly I am not sure they reduce the chance of leaks from plumbing issues, despite lots of people saying they are foolproof (fools are SO ingenious that's a hard standard to achieve).

I'm going to start making water today for a water change (I do RODI because our local water is so bad, so it takes me about 3 days to do 120 gallons or so I need for two tanks). I'll pick one apart a bit and see what I can find. Need to find the size of the o-rings, and if it's something I can get quickly I think just change them out. But if I get a bit brave (or a big bucket to put a filter in), I think I'll just remove the o-ring and see what the leak looks like -- does water flow out the same way I saw it doing when it flooded. That will perhaps not be conclusive, but it will be something of a smoking gun (or conversely, if it only runs out around the connector, it will be fairly conclusive that's not where it came from).


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## Nordic (Nov 11, 2003)

Order a drill bit off e-bay and drill it yourself. Look up for vids on youtube, not very hard.


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## Linwood (Jun 19, 2014)

Nordic said:


> Order a drill bit off e-bay and drill it yourself. Look up for vids on youtube, not very hard.


Could you elaborate just slightly... I've searched but I lack a context for what exactly I'm trying to drill and why? 

Maybe a link, or something?


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## PlantedRich (Jul 21, 2010)

I have no experience with that filter but your theory sounds solid! 
One thing that I do find is that it can pay to look around locally for O-rings before needing them or buying filter specific items from a fish place. 
Thinking about how O-rings fit down into a channel and are squeezed to make the seal, it makes it easy to think they will get deformed when left in the same shape for long periods. Sometimes a better seal can be found by taking the O-ring off and turning it over and around while adding a bit of petroleum jelly as lube. But since I found how cheap it is IF I can find a pretty close match, I now just have a stock of rings and change them out when in doubt. 
It gets down to 15-20 cents per when I buy a kit of various sizes from places like Harbor Freight.


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## Nordic (Nov 11, 2003)

> I can't do a sump easily because my tank is not drilled.


https://www.youtube.com/watch?v=LgIM5-kxwVE


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## Leeatl (Aug 8, 2015)

Another good place to get o rings is a dive shop if there is one near you . They have they good silicone grease too .


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## flutterbug (Jan 8, 2012)

Linwood said:


> I had read that some time ago, indeed I bought spare impeller and UV lights from them.
> 
> What I can't figure out though is what their retrofit actually entails. My impression is that it relates to the outer connection where the hoses attach (they speak of an elbow). Because mine are under the tank, the 45 degree now on them works nicely; if they had a 90 degree it would be more awkward.
> 
> ...


 I am wondering what their retrofit entails as well. It ups the price from an average of $85 to $130. I know part of it is the lava rock but I would rather just buy Matrix or similar myself. 
If the o-rings you need are for the quick release valve I know I saw those there. Let me know if it fixes it because as I am typing this my Sunsun is randomly shutting off and turning back on again. I spent my day messing with the tubing and had it back to how I used to have it before I added a CO2 reactor and I thought it fixed it because it was running for most of the day without shutting off. But now it is turning off and on every few minutes again.


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## Linwood (Jun 19, 2014)

OK, I got enough water made to change, and while doing it I took the filter that was failing last time, took the o-rings off that were on the tube attachment. I put it back together and turned it on, naturally it leaked like mad, but the water started coming out of the sides of the head (after filling it up) just as it does when it was failing more slowly. 

I had a spare set. I photographed them to compare:










The old ones are the larger - you can see they are significantly stretched; less obvious but they are also significantly thinner.

When I replaced them, putting the connectors back was also significantly more difficult -- a much tighter fit. Not so that it was difficult, but it made it clear the new o-rings were fitting tighter. 

It's hard to know if a problem is gone of course, but I have pretty high confidence that the problem was on these o-rings, not the big one.

I ordered several sets of the o-rings for these, and a couple more of the large (the shipping is about the same so I might as well get a bunch at once).


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## Linwood (Jun 19, 2014)

Well, I give up.

I have had two more leak, for a total of 3 (or maybe it was 4) events, all with fresh o-rings.

I keep thinking "maybe I didn't clean the receiver well" or "too much pressure to one side by the hoses" but they keep leaking.

So much for that theory.

The really horrible aspect of this is that they seem triggered to leak by not running, i.e. they either leak immediately upon assembly (when water floods back in), or they run just fine and dry, but when the power is cut off they start leaking.

Meaning any power failure I stand a good chance of a flood.

So far no floods while I was not home. But that luck can't last. The good news is this is on a tile floor, the bad news is if it flooded too badly the baseboard would be damaged, and of course the fish will die (well, if it hits the filter that draws from near the bottom of the tank).

So it is time to stop using SunSun's. I loved them, had four of them, but at about 2 years of age now (really only a bit over one year for one), they are just no longer usable due to the leaks.


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## Seattle_Aquarist (Jun 15, 2008)

Hi Linwood,

You might consider the Marineland Magniflow filters as an alternative; 3 year warranty, easy to clean, media and parts typically at LFS, 800# number for service and warranty support.


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## PlantedRich (Jul 21, 2010)

An alternate plan? While it is not a mod that I really like, there is a way to reduce the flood. Drilling a hole in the intake plastic somewhat near the top tank water level will make a siphon break when the water gets that low. It does stop flooding but it also has some downsides to figure in as well. If you use the siphon to drain water, it will require some type of stopper or cutoff for the hole. I can also see it would make restart priming a real bear as there would be no way to let it refill the canister while the break was working. 
I've considered the benefit/ downside and have not done the mod. But if the choice was to mod or to replace the filter, I would be tempted. 
A somewhat more complex idea might help. If one drilled a 10-32 size hole in the plastic and tapped it for a barb from an RC airplane place, it would let you fit airline tubing to the barb and a simple plastic air shut off valve that you place at the level you want the flood to stop. 
Normal operation, you could leave the valve open to break the siphon but close it when draining down for water changes so that the siphon is not lost. 
Wild plan and more effort, but then that seems to be where it is right now? 

I use this fitting for the Clippard parts and then have found it handy for other places. I bought a pack of ten and now am about out but if you are lucky, you can find the plastic/nylon type for around ten cents each.


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## Linwood (Jun 19, 2014)

Roy, thanks; that looks a bit smaller than the one SunSun, I do not think it would replace 2, though I might consider two of them I guess. I will do some reading; back long ago I recall they were not highly liked, but times change.

PlantedRich.. that's an interesting though. I think it might take some experimentation to see (as if the power came back on shortly after) whether the pump would pull enough air through that to stop all water flow. And yes, on one of these I do indeed let it pump the tank out for water changes; the airhose idea is nice (assuming I have enough memory to reset it to the right setting). 

Of course, let's say I allow for an inch fall -- I probably let almost that much evaporation happen at times. An inch in that tank is about 8 gallons. That saves the tank, still makes a pretty big mess though.

I wish I could figure out exactly where they are leaking -- I know the water is rising into the head, where it usually does not go, because when I open it up, a pint or so of water dumps out of the head. When I open it after running normally with no leaks, there's no water that comes out of the head.


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## PlantedRich (Jul 21, 2010)

An old repairman's dream job, huh? 
Fixing things is easy. It's finding the cause that takes time. I would like to think you are on the right track with the leak at the O-rings. They seem to be a likely spot.


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## Linwood (Jun 19, 2014)

Maybe, but I've replaced both the large and two small multiple times and still had leaks. Either they just do not fit tight enough and over time something stretches, or (more likely) it is something internal that is leaking from the water path into the head itself.

But regardless, I am very tired of cleaning up water, and it is time to throw them in the trash. Just need to pick a replacement, before this happens at a really bad time.

The problem is that even if magically I stumble on the fix, since it often takes weeks to leak again (or a few power outages -- this last one came after about the third since the last water change), it is very hard to know when it is "fixed", so short of finding a big hole that says "this is the leak, patch here", I'm weeks and weeks of worrying whether I have it fixed even if I get on the right track. Not worth it.

Glad I don't have carpet.


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## PlantedRich (Jul 21, 2010)

Got to agree! There is a time when we get around to admiting the hassle is not worth it. I am usually somewhat relieved when folks tell me something doesn't work at all. Those are much easier than something that works most of the time and only stop now and then. 
That is where I had finally settled on being able and ready to buy the Eheim 2075 that seemed to do everything I wanted and do it very well. That plan lasted only as long as it took for them to stop selling them! 
So I now have a new Sunsun 304B under one and still don't know what to expect.


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## PlantedRich (Jul 21, 2010)

As a small point on the SunSun filter? I now find it does have some trouble that effects me but might not effect others. I often find my tanks run warmer than other folks tanks. This is due in part to the way I set mine with full canopies and full stands with only the back open. With the new filter which draws quite a lot more power and setting under the tank, this new filter is running my tank warmer than the old Eheim 2217 it replaced. I have a daughter who struggles to keep the tank and filter cleaned so I moved the 2217 over to her and replaced it. I normally like to run 76 as the preferred temperature but this 75 has gradually climbed up to 80 even with the AC set to maintain 76 in the house. 
Sometimes it is the small points like power consumption that we miss when we consider buying the cheaper brands. 
Is it cheaper to buy low cost equipment which uses more electricity? That means higher bills for the filter but also, in my case, higher bills for the AC to cool it. So if it breaks down sooner, do I really want to "save" that money? 
I think I just bought a 35 watt heater to run 24-7! Maybe that's not very smart for me to do here. I now get to run a fan to move that heat out of the tank.


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## Linwood (Jun 19, 2014)

Well, maybe. And it could be indirect as well.

If you kept the same plumbing, the SunSun I think has almost twice the un-loaded gph? Actual power draw on filters tends to go up a lot more than linearly with pressure, so if you double the flow rate in the same plumbing, it can take 3-4 times the power to maintain it. My 59W SunSun (of which probably 12-15W is the UV light) might run at 10W without pressure, and 40W with pressure. In turbulent water flow the friction (i.e. heat) losses go up as the square of the flow rate.

The actual efficiency looks similar -- about half the wattage (subtracting for the light) as my 404B and about half the unloaded flow rate (I.e. "about" means the Eheim is about 12% more efficient if you believe the labels and ratings and guessing at the light). 

If you did keep the same plumbing, try opening it up a bit more - bigger holes, an additional output, etc. If you drop the flow speed down (you'll still have more total I think) you might find it draws a lot less power and generates less heat.


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## Chrissnailtrail (Apr 12, 2021)

Linwood said:


> I've been a fan on SunSun's and have 4 of these, most over a year running fine.
> 
> However, I am starting to be a bit less of a fan.
> 
> ...


I've had the same problems it's the O-rings on the inlet and Outlet if you're getting water in the head it's from the O-rings on the inlet and Outlet


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