View Full Version : PVC overflow

01-12-2004, 06:48 PM
Question about this PVC over flow.

01-12-2004, 06:52 PM
Please look at the 90 degree elbow on top of the overflow tube.

Is this elbow opened?

If I leave this elbow open, I can't start siphoning. Keep sucking the air and no water going through.

If I close the elbow using a cap, I can start siphoning.
However, when the water goes below the overflow tube, siphoning will not start upon refilling water.

I tried to temporarily close this elbow using my hand and let it go as soon as siphoning started. It works but water flows through the tube very weak.

Please tell me your trick to start this siphoning. And please let me know if I need to leave that elbow open or close.

Thanks a lot.


01-13-2004, 01:13 AM
you need to take the whole overflow assembly and submerse it in the tank. plug the bottom hole and the overflow hole with your fingers and hang it on the tank, after that you should always have a siphon on the left hand side, i'm pretty sure that's how it works, there are many variations to the same overflow. do a search on pvc overflows in the past year and you'll find others.

01-13-2004, 01:58 AM
Check this one out! A little easier to see how it works.


01-13-2004, 03:06 AM
limige, Thanks for the tip. I will try it.

Lem, Thanks for the link. Can you tell me how to start siphoning for that PVC overflow?


01-13-2004, 03:18 AM
Lem504, I read that article again and I think this PVC overflow is cool. Will try it tomorrow.
Thanks for the tip.

01-13-2004, 09:04 PM
You were given the right advice on starting these things.
Just stick it under water and get all of the air out.
If you have an air bubble trapped, it will cut the flow.
Have fun! ;D

01-14-2004, 12:00 AM
Hi Lem,
Believe it or not, I made one pvc today followed the photo you provided. It works fine. The only problem I am having is the sound when the PVC sucks air. How do you stop that sound?

01-14-2004, 08:06 PM
I built the same thing a while back and I don't have any noise whenit's in use. If you are using an R.O system my waste water goes into my angelfish tanks with the unit in place and that water goes out to the grass

01-14-2004, 11:45 PM
I built one like this one from Cary. It works fine but the gurling nois is terrible. If I close the opening of the T connector, the noise is gone but I will lose the siphoning whenever the Water pump turned off.

Cary, please give me some tips. How do I shut the noise up?

01-15-2004, 01:21 AM
I think I had the same problem with a home made filter,
Can't remember how I stopped it, but it was something that changed the water flow down the drain. Once it began to spiral the noise went away.

What about a cap or plug, on the top of the T fitting, with a small hole drilled in it. Should muffle the noise, and not screw up the syphon. ( start with a very small hole - you can always make it bigger )


01-15-2004, 03:18 AM
I did it but no help. It only changes the tone of the sound.
Someone told me that this kind of PVC overflow is designed to use with drip system, not to use with a water pump. May be drilling the tank or using overflow box is the right solution. Please give some input folks :).

01-15-2004, 07:46 AM
I know alot of people use those but I just cant trust those things.

buy a 1.5/8ths diamond core from www.ameriglass.com
a 1" female adapter a 1" male adapter 2 gaskets and you got a bulkhead that will out live your fish.

01-15-2004, 08:33 AM
That's a bad link Jason...


01-15-2004, 12:17 PM
NOw the majic question!!!!

I have at least one tank, that came with a note inside, indicating it was made with tempered glass
Big warning! "Do Not Drill a hole in the Bottom"
( wish I could remember which one it was )

Can tempered glass be drilled, or ground, or will
you wind up with a million pieces?


01-15-2004, 05:25 PM
this link will work

no you cannot drill tempered glass, not easily anyway. just side-drill the tank and install a bulkhead as you normaly would do, except use a 90d elbow to point your stand pipe up.

and don't drill your tank at the water line, drill it atleast half way down the height of the tank.

??? and whoever thought it was a good idea too tap tanks at the water should get a kick in the *** :spank:, or atleast come and patch my tanks ???

01-16-2004, 06:28 PM
I did it but no help. It only changes the tone of the sound.
Someone told me that this kind of PVC overflow is designed to use with drip system, not to use with a water pump. May be drilling the tank or using overflow box is the right solution. Please give some input folks :).

Hmm, how about a sponge over the end?

I get this problem with gurgling and whistling with a bulkhead at the water line, (yeah all 10 tanks are drilled at the 2" from the top, bought them used) I solved mine by decreasing the incoming flow rate.

I've yet to construct the overflow tubes for more flow (and to use the additional 2" of tank)

01-23-2004, 05:58 AM
You can cut down on the gurgling noise in a non-siphon overflow by making sure the pipe can get enough air in with the water so it doesn't tend to create air pockets on the way down, and by giving the noise almost no place to go (there is a reason that some musical instruments use long pieces of open pipe to amplify sound).

Here is a link to a very simple way to reduce pipe noise. It is set up for an internal overflow, but will work just as well if the intake is through a bulkhead in the wall. http://www.rl180reef.com/pages/standpipe/standpipe-open.htm and if you want DIY details, check here: http://www.rl180reef.com/pages/standpipe/construct-standpipe.htm

Hope this helps.

01-23-2004, 03:20 PM
I think I fixed the problem.
What I did is to make a PVC U shape tube. Insert one end of the U tube to the opening of the T connector. Insert a cap on the other end of the U tube and drill a 1/2" diameter hole in the center of the cap. This end of the U tube (with the cap) goes above the tank and goes down and touch the surface of the water. When the water is filling up to the hole, water closes the hole and no more noise. WHen the pump is turned off, water will drop below the hole and air will rush in to keep the siphoning.

I tested this modification and it is working great.

01-27-2004, 11:05 AM
Picture? Id love to see the modification! ;)

01-27-2004, 03:47 PM
Here is the photo.

01-27-2004, 03:52 PM
Sorry the photo is not that clear. But at least show you the idea.

On the cap at one end of the U tube, I drill a hole in the center of the Cap. When water surface touches this hole, the noise is gone.

Starting the siphoning for this overflow is easy. Take out the U tube, cover the opening of the T using your hand, and suck out the water at the drain tube. After siphoning is started, plug the U shape tube into the opening of the T connector and that is it.

It's been working great for me. Absolutely NO Noise.


01-27-2004, 04:06 PM
another one.

01-27-2004, 04:22 PM
Here is my Lab corner ;D.

01-28-2004, 03:10 PM
I would like to setup my first wet/dry filter by usinbg this PVC overflow method.

I have few questions
I have a 75Gal tank (with the stand) the height ia about 5 feet. I plan to use a 20 gal as a sump, is this size large enough? What size of the PVC pipe should I use? Another question is which pump is perfect for me since I am not sure about the outflow?

Thanks in advance for all your advice.

01-28-2004, 05:07 PM
I am currently using a 20 gallon sump for 3 tanks: one 55 gal, one 29 gals and one 20 gals. I am using 1" PVC for the drain pipe in the 55 gal and 3/4" in the 29 and 20 gals.

For the return water, I use 1/2" PVC. The return PVC goes up to the wall about 8' high and goes down to the tanks which is 7' high. I am using a Mag drive 7 and I have ball valves installed to control the flow.

So far this set up is working great for me.

01-28-2004, 05:58 PM
thanks td!! ;D

I will go to home depot, and do my research on my new wet/dry project

06-21-2004, 11:56 AM
when you made the modification to reduce the noise, when the power goes out do you loose siphon??? you you reccomed this type of overflow for a central system off about 3000 gallons? i think im going to have around 70 tanks. thanks