# PVC overflow noise reduction idea



## AF_medic (Jun 8, 2006)

ok, so I recently built my own sump, and I built my overflows using this ( http://www.cichlid-forum.com/articles/d ... erflow.php ) article from the library.

they work pretty well. but I have to have 2 of the overflows running at the same time, each with 2 1" siphons feeding it in order to keep up with my sump. and they aren't very quiet, and every time I change my water I have to re-do the siphons to the overflow boxes on back, so it's been kind of a p.i.a. and I've only had them running for about a month.

so I was looking at other designs that I should have found in the first place, and I noticed alot of discussion recently in the DIY forum on this very subject, alot of the discussion was not about whether or not their designs would work, but how to get the things quiet enough to live with them! especially if you're like me and have your aquarium in the living room. right next to the couch. and if you're like me, the sound of running water sends me running to the bathroom. :roll:

so, I was looking at the designs out there, and I noticed one design in particular that was prevailing in the discussions. I drew a little picture of it for ya.










now, I like this design because it would keep it's siphon even if I did my typical 50% weekly waterchange. which is something my current overflows can't do. my only qualm with it is that it wouldn't be any quieter than what I have now. so I was thinking about it, about how I could quiet the thing down. the noise comes from the water splashing and swirling and gurgling as it falls down an empty tube full of air leading down to your sump. that noise bounces out of the opening at the top, and sends me running for the bathroom. :? 
so I thought, all you need to do is isolate the bouncing sound from the opening at the top, and it should be quiet, right? so I drew another little picture for ya to illustrate my idea.










so, my question for you before I go and build this, is do you think that this will really cut out most if not all of the noise? it would still work the same, water level rises, water falls down into sump, water level drops, water stops falling into sump.

let me know what you think. and let me know if somebody else has had this idea before so I can ask them how it worked. [/img]


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## Mcdaphnia (Dec 16, 2003)

It might just double-gurgle, making even more noise. You can hear water flowing though plastic pipe even if you are a floor or two below any openings in the pipe, so enclosing the gurgle may not help. One way to reduce the gurgle is not to have a perfectly vertical drop. If the drop pipe is more diagonal, then water tends to flow on the side leaning toward it, making a more laminar less turbulent flow.


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## AF_medic (Jun 8, 2006)

I hadn't thought about the vertical drop thing. I might have to come up with an idea for that before I start making one of these.


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## boredatwork (Sep 14, 2007)

No. Noise in a drain pipe comes from the mixture of air and water in the drainpipe. If you don't get rid of the air, or reduce the air then you can't get rid of the noise. There are better, and simpler, ideas that can be used to muffle the noise - look up the hoffer gurgle buster.


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## AF_medic (Jun 8, 2006)

yeah, but the gurgle buster requires the box hanging off the back, which I want to get rid of because I lose siphon every water change.


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## Mcdaphnia (Dec 16, 2003)

AF_medic said:


> yeah, but the gurgle buster requires the box hanging off the back, which I want to get rid of because I lose siphon every water change.


 The purpose of the box is to preserve the siphon during low water. You should not lose your siphon, even if you lower water levels in the tank, but if you draw out the dump water from the sump, which is one of the ideas for having a sump, it is even more mystifying why the siphon could be lost.


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## mithesaint (Oct 31, 2006)

Have you looked at the MFK overflow design? It might not be any improvement on noise necessarily, but it would reliably restart every time. There are steps to silencing the MFK design too, but I haven't bothered taking them yet! Overflows that don't restart automatically make me nervous.

The design you posted would suffer a little because of the height of the outside T leading to the sump. With the T that high, you lose some of the siphon's power. Look at it this way. If you're using a plain old gravel vac to siphon water out of your tank, look at how much stronger the siphon is when you're going to a bucket on the floor. Now raise the siphon up to the level of the water, and the flow decreases significantly. That's what happens with the overflow you posted.


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## duaneS (Aug 31, 2006)

If you cover the "open" pipe with a loose fitting PVC cap, that you've drilled a 1/4" hole in the middle, noise will be drastically reduced.








I realize this is on a stand pipe, but the same principal applies to overflows.


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## Turtlemaxxx (Jul 13, 2007)

How do you lose the siphon when u do water changes? Are the U pipes getting air in them from the tank side or the box side? If you do a 50% water change are your tubes on the intake side still underwater? If not you could make them longer and not loose your siphon anymore. Then for noise reduction cut a sponge to fit the top of the box. The sponge will let air in and less noise out.

-matt


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## boredatwork (Sep 14, 2007)

AF_medic said:


> yeah, but the gurgle buster requires the box hanging off the back, which I want to get rid of because I lose siphon every water change.


You do not need the box. It is very similar to the cap idea shared by duaneS.

As I mentioned the noise in the drainpipe comes from the air being sucked into the drain. The air mixed with the turbulent water creates air bubbles in the water being drained to the sump. Essentially these bubbles are the equivalent of dropping marbles down a pipe. If you cannot prevent air from being sucked into the drainpipe then you cannot eliminate noise. The next best step is to limit the amount of air that gets sucked in. In your original picture you have a vent where air enters the drainpipe. This is the only place that you can try to control how much air gets in. You could place the cap, or a gurgle buster on top of the vent. And if you didn't want to have it looking like a chimney on top of your fish tank you could even put an upside PVC U on top of the vent to bring it down below the top of the tank and then put the gurgle buster on.

The advantage of the gurgle buster over the cap is that you can adjust the amount of air on the fly. With the cap you can do that, but only by drilling new holes.

In the design you copied from the library article you will not lose the siphon. That is the whole point of the first U on the outside of the tank.


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## AF_medic (Jun 8, 2006)

this is why I lose siphon every water change










I built a durso stand pipe on it, so it's not like it's horrible noisey, it's just nowhere near quiet.


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## AF_medic (Jun 8, 2006)

the overflow I built starts reliably every time the power goes out(simulated), but I change probably about 30-40gallons of water everyweek. I just like doing 50% water changes. the sump is a 20g tall, so I don't just empty out the sump for my water changes. that and I like taking my waterchanges from the main tank so I can vacuum out the **** and stuff that didn't make it to the filter.

quick question for you guys, how much of a water drop do you have when you turn off the power? meaning, when the water is on, how high is your water, compared to how high the water is off when you turn off the power?


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## Mcdaphnia (Dec 16, 2003)

AF_medic said:


> this is why I lose siphon every water change
> 
> 
> 
> ...


Install the parts you left out of the design and it will not lose siphon.


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## AF_medic (Jun 8, 2006)

mcdaphnia, did you read the article I built the overflow from?

http://www.cichlid-forum.com/articles/d ... erflow.php

I followed the article. it was just a poor design. so now I am going to try something new. the only thing you could do to this design to keep it from losing siphon is to put a u-turn on the intake, bring it up to the surface, and use it as a surface skimmer like the MFK design. other than that, nothing will keep it from losing siphon during a water change. that design should probably be taken out of the library actually, it's really not very good. the other ones that I've seen being talked about in the DIY forum are much better.


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## KaiserSousay (Nov 2, 2008)

Must just be getting old :-?



> AF_medic wrote:
> this is why I lose siphon every water change


Never seen water go up hill before :?


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## AF_medic (Jun 8, 2006)

I am hereby abandoning this thread, no help here, just wise cracks.


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## duaneS (Aug 31, 2006)

The pipe in the overflow box, leading to the sump looks a bit too tall, lower it a bit and you may not lose siphon.
And...Also as opposed taking water solely from the tank, take it from the sump and don't stop the pump (just guessing that's whats happening), that way the siphon is not broken.
When I do a water change I pump water partially to waste from the sump to a PVC T , but still pump partially to the tank, just down to the pumps impeller level.(don't like to let it run dry)








You can see by the water line how far the sump has dropped during the WC, but I do not discontinue pumping to the tank, the siphon and pump are still running.








The above pic is normal planted sump level


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## wheatbackdigger (May 11, 2008)

I use a Stockman standpipe and it did wonders (HOB overflow). Your design is seriously flawed. If designed correctly, you should be able to empty the tank and never loose the siphon.


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## boredatwork (Sep 14, 2007)

KaiserSousay said:


> Must just be getting old :-?
> 
> 
> 
> ...


I was thinking the same thing.

AF_medic, can you take a picture of the actual setup? The drawing must not accurately reflect what you built.

Think about it this way. This is not a unique design. Many people have used it successfully and practically there is no flaw in the design. If you can show up what your actual setup looks like we might be able to figure out what is wrong.


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## imusuallyuseless (Dec 28, 2005)

I would tend to agree a pic would help a ton. I just don't see why your overflow box would continue draining once below the top of the standpipe...


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## KaiserSousay (Nov 2, 2008)

OK..after a few PM`s ..what is happining, during water changes, the overflow box is siphoning back to the tank..when new water is put in, has to get the air out of U tubes to start flow again.
His lift tubes are way deep in the tank, just above bottom. 
Just a PIA to restart is the problem.
Thought about a hole in U tube, box side, below nomal waterline??


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## imusuallyuseless (Dec 28, 2005)

Now that makes sense.

A custom ultra deep overflow box on the outside would help or doing a lower percentage water change. Could also try pumping water in while siphoning out but that could get tricky to say the least :lol:


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## KaiserSousay (Nov 2, 2008)

Seems the consensus on this problem is to do your water changes in the sump.
The only alternative I could think of is to drill your U tube, put a tubing fitting at the top, length of tubing with a check valve which would make getting your siphon going again easier.


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## duaneS (Aug 31, 2006)

Just a thought, the place where the worst stuff, the stuff that you really want to get rid of, be it DOC, oils, amino acids, etc. is the air/water interface, which is the waters surface. Having your intake so low in the tank picks up detritus, but does little to deal with the above. On of the reasons an overflow/stand pipe (surface skimmer) is effective.
This is why protein skimming is used, the air/water interface (bubble, or surface) is where pollutants naturally collect.


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## jwal (Jan 17, 2008)

I'm not sure if this has been pointed out yet, but you should have a box inside the tank that holds water, if you want to prevent losing prime on your siphon


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