# Still having a nightmare with sump, please help!



## Abi Jones (20 Nov 2020)

Every time I start up the pump again after doing maintenance the flow into the sump starts surging, by this I mean that instead of a constant flow into the sump it’s alternating between niagara falls and a trickle. Does anyone have any ideas why it would be doing that? It usually evens out after a day or two but I’m sure this shouldn’t be happening and it’s extremely annoying! I have a durso up top and a reverse durso at the sump, with just coarse sponge in the first chamber.




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## ScareCrow (20 Nov 2020)

Hi Abi, could you post a pic of the reverse durso? It's hard to see the top of the upstand on the left, which helps remove air. From the video, it looks to me like it's creating a vacuum in the system.
In your other thread about the noise coming from the sump. It might be worth adding a small adjustable valve to the top of the cap. It might not make much/any difference if the hole is already the optimal size but it would allow you to tune the amount of air entering the system.


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## Abi Jones (20 Nov 2020)

ScareCrow said:


> Hi Abi, could you post a pic of the reverse durso? It's hard to see the top of the upstand on the left, which helps remove air. From the video, it looks to me like it's creating a vacuum in the system.
> In your other thread about the noise coming from the sump. It might be worth adding a small adjustable valve to the top of the cap. It might not make much/any difference if the hole is already the optimal size but it would allow you to tune the amount of air entering the system.







Thanks so much for replying, I feel like I’m never going to get this right! Where exactly would I put the valve? The dursos are both a bit thrown together and prob not ideal- it is noisier without them but it’s by no means quiet with! I think you’re right about the vacuum, I was worried there was pressure building up somewhere and then releasing causing the fluctuating flow. 


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## ScareCrow (20 Nov 2020)

I'd put the valve in the hole in the overflow cap (see pic). Can you explain what the arrangement is with the reverse durso, in regards to the plack hoses? Is the top capped off and are those connected through the cap?
If you pull the black sponge out from under outflow pipe, so the flow isn't restricted, does it still pulse?


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## Abi Jones (20 Nov 2020)

ScareCrow said:


> I'd put the valve in the hole in the overflow cap (see pic). Can you explain what the arrangement is with the reverse durso, in regards to the plack hoses? Is the top capped off and are those connected through the cap?
> If you pull the black sponge out from under outflow pipe, so the flow isn't restricted, does it still pulse?
> View attachment 156639



They are to let air out. I read that was what you were supposed to do, is that wrong? Without the cap with air hoses it gurgles really badly. I haven’t tried without the sponge at all but it’s quite open cell and doesn’t go all the way to the bottom of the chamber. I’ll take it out tomorrow and see if that helps. The top durso doesn’t look like that anymore, I’ll take a pic.


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## Ed Wiser (20 Nov 2020)

Who suggested a dorso at the outlet into the sump. I have been using sumos for 35 years in Saltwater and have visited thousands on people’s homes across the USA. This is going to cause flow balance issues. No wonder you are having an issue. The dorso method was developed by a friend of my years ago. It was developed to remove the suction of air down the overflow from the tank into the sump. When you block the outflow of water into the sump water will back up into Down tube pipe. This cause a flow imbalance.


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## Abi Jones (20 Nov 2020)

Ed Wiser said:


> Who suggested a dorso at the outlet into the sump. I have been using sumos for 35 years in Saltwater and have visited thousands on people’s homes across the USA. This is going to cause flow balance issues. No wonder you are having an issue. The dorso method was developed by a friend of my years ago. It was developed to remove the suction of air down the overflow from the tank into the sump. When you block the outflow of water into the sump water will back up into Down tube pipe. This cause a flow imbalance.



I can’t remember where I read it, but was having noise issues so gave it a go and it did help with the noise a little. I’ve just tried taking the reverse durso at the sump off and having water flow unrestricted into the sump, it still does the surging thing  So I presume it must be an issue with the top durso? If I take photos of the whole set up tomorrow and post here would you mind advising? 


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## ScareCrow (20 Nov 2020)

Yeah it would be good to see how the whole system is working. I'd leave the bottom durso off and try to get the top working efficiently before adding complications lower down. The bottom durso shouldn't be restricting the flow though, as it's still a straight path for the water. All the bottom durso is trying to do is remove some of the air before it gets into the sump, reducing turbulence and noise. The black sponge might have been restricting the flow if the down pipe was pressed up against it but if you've removed the bottom durso and still have the pulsing issue it's not the cause.


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## Abi Jones (20 Nov 2020)

ScareCrow said:


> Yeah it would be good to see how the whole system is working. I'd leave the bottom durso off and try to get the top working efficiently before adding complications lower down. The bottom durso shouldn't be restricting the flow though, as it's still a straight path for the water. All the bottom durso is trying to do is remove some of the air before it gets into the sump, reducing turbulence and noise. The black sponge might have been restricting the flow if the down pipe was pressed up against it but if you've removed the bottom durso and still have the pulsing issue it's not the cause.



Thanks so much for helping, I’ll be back tomorrow. At this point I’ve just had enough of the whole sump thing, it shouldn’t be this difficult to get right! 


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## Ed Wiser (20 Nov 2020)

The issue is the top unit. Did you make this yourself or but it. This pretty basic overflow design now days.


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## Abi Jones (21 Nov 2020)

ScareCrow said:


> Yeah it would be good to see how the whole system is working. I'd leave the bottom durso off and try to get the top working efficiently before adding complications lower down. The bottom durso shouldn't be restricting the flow though, as it's still a straight path for the water. All the bottom durso is trying to do is remove some of the air before it gets into the sump, reducing turbulence and noise. The black sponge might have been restricting the flow if the down pipe was pressed up against it but if you've removed the bottom durso and still have the pulsing issue it's not the cause.



This is the top durso, it did have 2 air lines but added a third and its now stopped surging, is still pretty bubbly where it enters the sump tho.











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## Abi Jones (21 Nov 2020)

Ed Wiser said:


> The issue is the top unit. Did you make this yourself or but it. This pretty basic overflow design now days.




The one shown by scarecrow above came with the tank, the one I’ve posted here today we made to replace it. 


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## ScareCrow (21 Nov 2020)

It certainly looks better than what was there before. It's hard to see from the picture but are the airlines drilled through a cap? The video that Ed posted shows exactly what I was talking about in regards to adding a valve to tune the air flow into the standpipe. That should be all that's needed to get the top of the durso working properly.


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## Abi Jones (22 Nov 2020)

ScareCrow said:


> It certainly looks better than what was there before. It's hard to see from the picture but are the airlines drilled through a cap? The video that Ed posted shows exactly what I was talking about in regards to adding a valve to tune the air flow into the standpipe. That should be all that's needed to get the top of the durso working properly.



Yes they are. I will try and find a valve for the top then, do you think I should ditch the reverse durso at the sump? 


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## ScareCrow (22 Nov 2020)

It's a bit of an odd situation. It shouldn't take three lines to vent the stand pipe. I'd stick a valve on each and slowly open one at a time to try and tune the airflow/water level, as the guy in Ed's video demonstrates. When the upper durso is working as good as you can get it, then I'd move to the lower one, if you still feel you need to reduce the noise. I think your reverse durso design was fine, it might be worth adding a bit more length so the bottom of the pipe is below the waterline. There are a few designs discussed here:


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## Abi Jones (22 Nov 2020)

ScareCrow said:


> It's a bit of an odd situation. It shouldn't take three lines to vent the stand pipe.




Yes that’s why I’m getting so frustrated! I’ll get another cap for the durso and try one larger airline with a valve. Is the point of the airline to vent air out of the system to avoid bubbling? So the more air I can release at the top the less turbulence in the sump is that right? And then the reverse durso gets rid of any air that’s still present.


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## ScareCrow (22 Nov 2020)

So the vent at the top, is to restrict the amount of air entering the system. You need to have some for water to be able to enter the stand pipe but excess air results in more noise. You want to reach a compromise between noise and flow. Be mindful that you can't totally cut off the air entering the stand pipe and you'll need to make sure that the valve doesn't get blocked. Otherwise you could have the tank overflow or your return pump run dry. (depending on your pump/sump arrangement, I don't know the layout of your sump, pump position if you have a secondary overflow or volume, so this might not be a concern).
As you say the reverse durso is trying to separate the air, that you had to let in at the top, from the water before it gets into the sump and in doing so reducing bubbling, turbulence and noise.


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## not called Bob (22 Nov 2020)

Abi Jones said:


> This is the top durso, it did have 2 air lines but added a third and its now stopped surging, is still pretty bubbly where it enters the sump tho.
> 
> 
> 
> ...


Is yours a single down pipe? Not seen so much water held there

Mines a nuts hight above the glass base and an emergency pipe half way up with its own hole in base


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## Abi Jones (22 Nov 2020)

not called Bob said:


> Is yours a single down pipe? Not seen so much water held there
> 
> Mines a nuts hight above the glass base and an emergency pipe half way up with its own hole in base



Yes it’s a single pipe down. I couldn’t make it any shorter as didn’t start messing about with it until it was filled so can’t cut the down pipe 


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## not called Bob (22 Nov 2020)

oh right, I have three pipes, two for water going down
one with a ball valve for balancing and a second for emergency use if first blocks, just a straight run
third is the pipe returning water back up again

sometimes if some airs trapped I turn the ball valve to closed, let a head build up and then open back to the mark on the pipe and the extra water rushing down pushes out all the trapped air and silences the setup,


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## zozo (23 Nov 2020)

The surging is caused by a capacity issue and a single pipe that actually is submerged at both ends. At the top the water is overflowing into it and at the bottom, this pipe stands in a puddle of water. The pipe will fill up entirely from top to bottom and water forced down by its own weight (gravity) and drags in the air with it causing an eddy, a surge with gurgling noises.

When such an air-bubble is in the pipe it actually counteracts gravity, it wants to float and rise to the top to escape. But it can't it is dragged down encapsulated in the water flow. Thus these forces are working against each other making the air-bubble dance up and down in the pipe slowly going further down or stay put dancing, till the weight above it as enough to make it shoot out.

This effect creates an erratic flow speed in the pipe. The water flow slows down by the dancing air-bubble(s) and speeds up the moment the bubble shoots through. It will make a bubbling noise in the sump and the sudden Waterflow acceleration in the pipe and at the top, it sucks in a new bubble making a gurgling noise.

I can imagine it is difficult to imagine or depict this happening from a description... But you could observe this rather natural effect happening if you would make it with transparent tubing.  I once did and discovered to the origin of the problem by seeing it happen.

It also can happen in an erratic pattern, no issues for days or even weeks and then suddenly start again... Water in pipes dragged down by gravity doesn't have a constant. Sucked in air bubbles differ in size and amount and at one point there will be a threshold playing up. Once a fluctuating flow pattern occurs it keeps itself alive.

What you can do to prevent this is actually very simple...  This is to divide the drain into 2 separate parts, both connected but as an open system so that air can get in somewhere else than from the top only and the pipe will not be filled entirely with water. To explain this I'll make a little diagram to make it a bit more clear.




The open connection allows air to get in and the overflow standpipe will never be filled with water and suck in no air bubbles. (If it still does it means this pipe is still too long and or too small. You should create an open connection as close to the tank possible.) The piece of horizontal pipe is also needed to prevent water from a deep fall into the sump creating a splashing noise. If you still hear water running noise from the open connection then plug this open connection with a piece of filter sponge. This dampens the noise coming out but still allows air in.

And your noise problems are about over.


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## Abi Jones (23 Nov 2020)

Thanks for that, it does make sense. When I first asked for help with this issue a few weeks back before I had any dursos other than the very crude one that came with the used tank we actually had a set up similar to the one in your diagram, only the horizontal pipe was a lot shorter and there was no open connection, the pic is of the previous set up. It was gurgling like mad and the first person to reply said, why haven’t you got the drain going straight down into the sump?! So we changed it!
Im not sure I understand the open connection part, should the air be escaping out of the pipe at that point, so the pipes shouldn’t fit properly together?  




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## zozo (23 Nov 2020)

As said before it's a capacity issue, the noises you hear is air sucked in with the water... This can only happen if you want to drain more than the pipe actually can handle. It needs aeration to function... Unfortunately, I can not create an animated example for you to show what actually is happening and what makes the noise. I can only try to describe it the best as possible in my own words. And I know this ain't that easy and it might be an air-castle for you.

What you have now is a pipe that stands in the sump submerged. Therefore the pipe will fill up partially probably more than 70% with water falling into the sump. You have only one point that aerates and that's the overflow in the tank. The volume in the pipe falls down and drags air with it. That's the noise, this creates a bubble in the pipes water volume slowing down the drain capacity because the bubble wants back out at the top but can't. The moment the bubble shoots out at the other end submerged you'll have a noise again. The water speeds up and sucks back a bubble at the top again noise. And this keeps going on and on.

So you need to create a different entrance and exit point for air to get in and or escape. It shouldn't be trapped in the entire pipes water volume. This you can do for example to unscrew the bulkhead from the standpipe in the picture and replace it with some sort of a Funnel. Made from a bigger size socket slided over so the stand pipe is in it and from that socket lead tubing to the sump. Then the pipes will not fill up with water and drain faster. Air that comes in via the overflow escapes via the open funnel.




You should make sure that the tubing to the sump functions as an open gutter can handle the volume, thus make it a tad bigger than the overflow pipe.

In a simple diagram, it looks like this. Red square in your picture.


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## zozo (23 Nov 2020)

Here is a picture of my overflow I hope it makes it more clear, it's a different type overflow but that doesn't change the fact that it can have the same noise issues if installed incorrectly.




You see the overflow pipe stands in a bigger pipe and this bigger pipe is the gutter to the sump. It's open. And this setup is since this adaptation as quiet as a mouse.


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## Abi Jones (23 Nov 2020)

Thank you so much taking the time to explain, I understand it now. I’ll have a go at adapting my set up today and will let you know how it goes 


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## Abi Jones (23 Nov 2020)

One more quick question, is the diagonal cut off at the bottom of standpipe important or is it ok to just have the standpipe ending in a straight edge inside the larger pipe? 


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## zozo (24 Nov 2020)

Abi Jones said:


> One more quick question, is the diagonal cut off at the bottom of standpipe important or is it ok to just have the standpipe ending in a straight edge inside the larger pipe?
> 
> 
> Sent from my iPhone using Tapatalk



Good observation and question.  And yes it can be important depending on the situation, where the standpipe ends. And it can also prevent the sound of falling or dripping water. In my case, it is important because of the pipe stands freely in a wider 90° knee on a horizontal surface without the use of any brackets. Obviously, I needed to cut it diagonally, because a straight cut would block the flow.

The other reason I also noticed if a pipe ends in a straight cut hovering above a horizontal surface (let us say the gutter) then the water will fall on it making a constant splashing or dripping or in some cases a peeing noise of water falling in the water below it. Noises like this can get amplified significantly when it needs to get out through an open aerated tube. And you'll hear a constant peeing concert. Then with a diagonal cut, you can make the pipe touch the surface and water it needs flow into more directly without falling and you still have aeration and it's silent.

These can be the little things but key points to take into account to get sump setups to be as quiet as possible. Prevent water from falling and splashing to much and maintain good aeration.

To clarify I refer to the first diagram I posted with the standpipe internal diagonal cut in the open connection goes al the way to the end.




In the second diagram with the straight cut hovering, this could/will make noise from falling water.




The external diagonal cut you see in the picture from my overflow is not that important but creates an easier entrance if taken apart for maintenance. And I could drill a hole to mount the tube to the wall with a screw, without the use of a bracket.


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## Abi Jones (24 Nov 2020)

Thanks for the clarification, it’s very much appreciated  Off to b@q shortly to try to find some parts, just hope we can find an elbow big enough to create the air gap as I think the down pipe is 40mm.


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## zozo (24 Nov 2020)

Abi Jones said:


> Thanks for the clarification, it’s very much appreciated  Off to b@q shortly to try to find some parts, just hope we can find an elbow big enough to create the air gap as I think the down pipe is 40mm.
> 
> 
> Sent from my iPhone using Tapatalk



I'm not sure about the UK, but mainland Europe the PVC pipe in Metric DIN standard is to jump from 40mm to 50mm.


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## not called Bob (24 Nov 2020)

is the double sleeve just recreating the small air gap having the downpipes terminate just above the water line?


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## Rainbow (21 Dec 2020)

Looks like your water level is right at the top of your Durso. This means you have very little room for the piping to take away the water before a syphon develops, sucking the bit of water there away very quickly. If you cannot drill another drain that is a bit smaller to take a full syphon constantly, I suggest a smaller return pump. That way you have constant flow through the Durso without a syphon.


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## Abi Jones (21 Dec 2020)

I gave up on it, tried everything everyone advised but nothing worked  I have a fluval f6 now and it’s super quiet- shame I still have a standpipe taking up loads of space. Think I’ll be looking for a new tank after Xmas!


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## not called Bob (21 Dec 2020)

could just block it off, until such time some one can pop round and assist


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## zozo (22 Dec 2020)

Abi Jones said:


> I gave up on it, tried everything everyone advised but nothing worked  I have a fluval f6 now and it’s super quiet- shame I still have a standpipe taking up loads of space. Think I’ll be looking for a new tank after Xmas!
> 
> 
> Sent from my iPhone using Tapatalk



As said before it's a capacity issue...  In this case, your pump is too strong... Pump and drain capacity should be in sync...

The easiest way to find out the drains optimal L/h capacity is a simple modification. That is to place a T splitter in the hose with a valve to it. Best is the place the T and valve in the sump as close as possible to the pump.



Thus the valve fully closed, then the pump runs full capacity to the tank. Open the valve a little and some water will run back into the sump and the aquarium will get a bit less, this way you can easily regulate how much water will be pumped to the tank and the turnover can be synced with the drain capacity.

Depending on the type of valve used it can be regulated pretty precise. Start with a little and just keep opening the valve a tad further in small steps each time till the drain is quiet. At this point, you have reached the drains maximum capacity.  And that's physics you simply can not stress and it is what it is without a bigger drainpipe.


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