# Overflow Help



## ksauke (May 7, 2008)

I'm in the process of starting up my 55G tank again and this time I decided to use a sump which lives in my basement. So I built 2 3/4" PVC overflows that run down to the sump in the basement. The problem I'm running into is that I can't seem to get much flow through them at all. To keep the tank from running over I have to throttle the pump way down. Turns out that I get about 60 GPH MAX combined flow through the overflows, or 30 GPH each. That is about 10% of what they should be getting. Below is a super high resolution drawing of what I'm doing. Any help would be appreciated.

Thanks,


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## fishwolfe (Mar 27, 2005)

i think that the T that directs the water to the sump needs to be higher unless you have a hole up top to break the siphon.most have the T closer to the top.with the T higher you would have more water pressure in the over flow,i believe.im sure someone else will chime in.


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## ksauke (May 7, 2008)

There is nothing on the top of the pipe over the T. I have tried putting a cap on it but after about 15 minutes the overflow started making this aweful sucking sound and then I lost the prime in the syphon and water stopped flowing completely.

I can try moving the T up further, the question is, how far? Should it be just below the tank water line or about halfway?


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## IrkedCitizen (Apr 26, 2007)

Is the overflow the complete length of the tank? If so that is most likely your problem. The water is having to travel from one side of the tank to the other side before exiting over the tank and then down/out to your wet/dry sump.

Make them smaller/more compact and see if that makes a difference.

They don't have to be big. The T fitting where the water drains to the wet/dry just has to be lower than the waterline. It does not have a tube out of the top of the T as it is not needed. You do not want to cap the T.

This one is made of 3/4" PVC and stretched out to show basic parts. When it is running it is turned to be compact.


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## ksauke (May 7, 2008)

After much fussing and experimenting, I still am unable to get more than about 30 GPH out of a 3/4" overflow. I changed my design to match yours almost exactly and I still can't get much water to flow through it. I'm pulling out my hair because I don't know where else to look.

The only modifications that I made to mine that I don't see on your picture above is 1 90 degree elbow on the intake side, and there is a airline checkvalve at the top where the syphon lives.

Anyone else ever have problems getting one of these running? I'm starting to lose my mind.


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## IrkedCitizen (Apr 26, 2007)

Try building one exactly like the one in my picture. Don't modify it to suit your needs as you just have to get more water movement through it first. You can build it out of 1" if you want and you don't have to use the clear tubing. You can also try it with the PVC pipe in longer lengths and lower the T fitting.

People have great success with these so I don't know why you are having any problems. Whatever you do don't go bigger then 1.25" as the flow isn't all that great.

How do you know exactly how many GPH you are getting through the overflow? What kind of pump are you using? How many foot of head is it pushing? The overflow will only drain as much water as the pump can return to the tank.


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## ksauke (May 7, 2008)

It is made out of PVC....here is a picture of it. Hopefully this helps. I attempted to paint it black with the Krylon Fusion paint but all my fussing with it has scratched the paint 

I guessed on the flow by holding a container under where it drains into the sump for 30 seconds and measured how much water came out of it.

I'm using a little giant 3MDC or something like that. It should pump about 400 GPH at the head that I'm running at. Currently I turn on my pump on for like 5 minutes until it almost overflows my tank and then it takes almost 15 minutes for the tank to drain back down to where it started.


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## IrkedCitizen (Apr 26, 2007)

What are the things I circled in red? Are they couplings or something else?


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## ksauke (May 7, 2008)

Yes, Couplings. I used them to cut down the vertical length the water had to travel. It was much longer before today.


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## IrkedCitizen (Apr 26, 2007)

Is there anyway for something to be stuck inside of the pipe hindering the flow?


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## ksauke (May 7, 2008)

I highly doubt it. I'll check but I've taken it apart so many times today I think I would have noticed something in there.


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## IrkedCitizen (Apr 26, 2007)

Okay well if there isn't anything hindering the flow I would build a new one out of 1". Have 2 pipes be 9" long, 1 pipe that is 6-8" long(which is determined by where you want the waterline) might as well start it long and then cut it down afterward to where you want it, 1 pipe 3" long, 4 pipes that are 1-1.5" long, 7 90's, 1 T, and then a length of pipe to get to your sump.

1. Put it together with the 6-8" pipe and 1 of the 9" pipes with a 90 at the bottom of each then use a 1-1.5" pipe to connect them in a U shape and that is the piece inside the tank.

2. Put 2 90's together with a 1-1.5" pipe and attach one of the 90's to the 9" length of pipe from the U you just built.

3. Put 2 90's together a 1-1.5" long pipe and attach the last 9" pipe and the 3" pipe. Put the T on the 3" pipe and the connect the 9" pipe to other 90 that you just added to the U shape.

4. Put the last 1-1.5" pipe to the last 90 and attach it to the T and then you are ready to add the length of pipe to get the water to the sump.

There is no need to glue it just push the pieces together really hard. It isn't under pressure so it will not leak. Don't mess with those 90's that you added to the intake. We just need to get you up and running.

I also do not use air check valves as I have the clear tubing so I can see if air is collecting.

I did a rough sketch in MS Paint of how I prime mine. Since it isn't glued together you can turn the pieces to make this shape.








Then pour water in the intake until it fills the pipe and starts to come out of the T. Then you rotate the pieces to make it the overflow shape and it should hold the water and there shouldn't be any air inside.


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## ksauke (May 7, 2008)

I'll have to try and build that tomorrow after a trip to Menards. I have managed to get my flow up to 81 GPH by removing the 90 elbow on the intake and I also modified my check valve so that the stem didn't protrude into the top of the overflow. Before it would sit inside about 1/8" so I think there was a small pocket of air at the top. That air should be gone now. I'm going to try your clear tubing trick too to make sure I don't have any air at the top.

How much flow did you get through your 3/4" overflow? The online calculator says I should get around 325 GPH.


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## IrkedCitizen (Apr 26, 2007)

ksauke said:


> How much flow did you get through your 3/4" overflow? The online calculator says I should get around 325 GPH.


I don't know for sure. I haven't had any issues like you are having to have to try and figure it out. I get enough flow that I am satisfied with it.

When using 1" you should be able to get 600gph so with two of those when fully functioning your pump shouldn't need to be unplugged or throttled back.


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## ksauke (May 7, 2008)

OK...Looks like I've got it working with the 3/4" PVC. I have my pump running fully open and with both overflows its able to keep up. The water level has leveled off though about 1" above the top of the overflows. Is that normal? I expected the water level to stay constant at the height or just a little higher than the intake, not a full 1" above it. Its been running for almost 3 hours now though so its been pretty stable.

It is quite loud. I drilled a hole in a cap for air and stuffed some cotton in the cap and that has helped some but there is still quite a gurgle coming out of the top of the T. Anyone have any ideas on how to muffle that?


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## IrkedCitizen (Apr 26, 2007)

What did you do to get it to work? You can always make the intake pipe taller so that there isn't as much of a gap at the top.

To get the noise quieter the pipe leading to the sump should not be completely vertical. Angle the 90 that is leading down to the sump and that should quiet it down and you should be able to take the cap off and the cotton out.

What is causing the noise is that the the draining water is hitting the air that is trying to escape which creates a vortex type thing that makes a gurgle/flushing noise. So angling the pipe makes it so the water travels along one side and the air is able to escape over the top of it.


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## ksauke (May 7, 2008)

I didn't really do anything to get it to work. It just all of a sudden started to flow, I have no idea what I was doing wrong before, it seems such a simple thing. There must have been an air pocket somewhere that I wasn't getting out properly.

I've managed to quiet it down now, no more gurgling. What I did was take a piece of airline tubing and threaded it all the way down the overflow so the end was just a couple inches from the 90 elbow where it makes its final descent into the sump. I also threaded it back through the hole in the cap and left the cotton in place. Worked great, sounds quiet and I think it has improved the flow.

Thanks much for all your help. It is very much appreciated!!!


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## IrkedCitizen (Apr 26, 2007)

No worries man. I try to help out when I can.


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