Noisy Gurgling Overflow - SOLVED!!!!

[Ron99]

I am still fiddling with this 75 gallon tank. it has a single overflow in the upper left corner. It's a 1.5 inch bulkhead and I've got an external Durso type of arrangement. The T section is made of 1.5" PVC. I have a short length of 1.25" hose and then it is reduced to 1" hose. I cannot get this to be quiet. It gurgles loudly all the time. I have tried using everything between 1.25" hose to 0.75" hose down to the sump. The 0.75" hose made it fairly quiet if I pretty much maxed out the flow so almost no air was going down the line but then I worry about something further reducing the flow down the line and ending up with the tank overflowing. I have also tried numerous hole configurations and sizes in the cap at the top and also putting airline down to various depths. Nothing works.

I hope somebody has insights into setting up an overflow with only one drain of this type.

Here's a pic:

http://hotimg25.fotki.com/a/70_70/254_23/Durso.jpg

[dkcrx]

have you tried useing hard line (pvc) to the sump?
I have mine set up that way, and remove the air line from the top of your pvc cap, mine only makes noise when the small hole in the cap starts to plug with salt, acts as a warning to clean it out.

http://i106.photobucket.com/albums/m267/dkcrx/DeanShaunasreefNov2008061.jpg

[fkshiu]

Some suggestions:

- as mentioned try using a hard line all the way down to the sump
- using a sanitary T (I know, they're hard to find in PVC) would help
- tap some threads into the hole at the top and screw in a JG ball valve.

I think the final suggestion would have the most effect because a Durso is all about controlling the amount of air that gets mixed with water. With the ball valve you'll be able to do that. I remember back in the day (waay back) when Wendell at OA first showed me how his Dursos worked with ball valves controlling air intake.

[banditpowdercoat]

Your vent hose is to large in Diameter. It's not matching the drain size to the cap hole, but matching the cap hole to the flow requirements. I have 6 0.018" holes in my cap for venting, about 300GPH drain. and it's silent. Try getting a shutoff on the vent, something you can precicely throttle back untill it's silent.

[mark]

Your vent hose is to large in Diameter. It's not matching the drain size to the cap hole, but matching the cap hole to the flow requirements. I have 6 0.018" holes in my cap for venting, about 300GPH drain. and it's silent. Try getting a shutoff on the vent, something you can precicely throttle back untill it's silent.

found with my 2" Dursos running between 500 and 1000gph, hole size in each is only around 1/8"

[Tom R]

I find that using Spaflex tubing helps muffle the sound. Spaflex tubing is available at most Hot Tub stores if they do installation.

Tom R

[Ron99]

Thanks for all the input. I have tried to replicate the valved vent by drilling a larger hole then taping it closed and using a pin to slowly enlarge a hole in the tape. All it does is affect the height of the water in the overflow box but little to quiet the gurgling. I'm not sure using solid pipe or spaflex will help muffle noise as it seems to be the gurgling of air at the T that is then being amplified in the T itself and sounding loud if that makes sense. But I may give it a try.

dkcrx, it looks like you have your pipe at about a 45 degree angle. This is why I used flexible tube as I need to go to the opening in the stand that is in the middle but the overflow is on the side. So I may need to angle the pipe as well and then use a couple of 45 degree elbows to get into the stand and sump. Would you mind posting a picture of the your configuration at the sump as well?

But as I said, most of the noise seems to be the gurgling at the T where the air/water interface is fairly turbulent and alot of air is being sucked down into the plumbing.

[Ron99]

Also, do you guys run the same diameter pipe all the way down from the bulkhead or do you decrease it at some point?

Thanks.

[whatcaneyedo]

Your overflow looks like mine... I've got some time off coming up soon so I'm just going to put everything from my display tank into the sump and bring the tank into a glass shop to get a second hole drilled for a herbie style overflow.

[dkcrx]

Also, do you guys run the same diameter pipe all the way down from the bulkhead or do you decrease it at some point?

Thanks.

Same size all the way to the sump, and I have one 90deg turn in the pipe

[achilles101]

I have the same tank I did an external durso drilled hole in cap to 1/4 it was noisey so used silcone to make smaller about 1/8. It had 2in sch 40 pvc pipe on it when I bought in but I used 2in sch 40 pvc for durso and then went to flexible 2in pipe for ponds. It is quiet and Im flowing about 900gph. Much like dkcrx's but not at angle.

[golf nut]

Also, do you guys run the same diameter pipe all the way down from the bulkhead or do you decrease it at some point?

Thanks.
That looks like the cause of your problem, your overflow is becoming a syphon due to the number of reductions you have made with adapters.

[chris121277]

I would try throttling back your return pump.......I have HOB over flow that claims to be rated for 1200 gph, and I tried everything to make it quite.
The only thing that worked for me was to back off the return pump to about half.

Here is a great article on reducing the noise from your overflow

http://www.wetwebmedia.com/SystemPIX/PlumbingPix/Oneinchart.htm

Hope that helps

[Ron99]

OK, I changed the overflow and line to straight 1.5" pipe all the way down to the sump and if anything it is noisier now! It is a swirling rushing water sound. Not flushing and not even really gurgling. The sound of water rushing down pipes. Like if somebody upstairs flushes a toilet and you hear the water rushing down the pipe.

The T at the bulkhead and pipe are angled down at roughly 45 degrees and I used only 45 degree elbows to get it down into the sump so there are no hard turns for the water to make.

I've also tried increasing or decreasing the flow from the return pump. Doesn't seem to help.

This thing is driving me nuts as I can't get it quiet. Help please!!!!

[golf nut]

Does the drain pipe go under the surface of the water in the sump?

[Ron99]

It does go under the water in the sump.

[golf nut]

Is it possible to raise it above the surface?

[fkshiu]

Is it possible to raise it above the surface?

Juuuuust above the surface so the air that has been introduced up top can escape. Having the pipe come down at an angle and then putting a 90 elbow on the end at the bottom about halfway submerged worked best when I ran a Durso/Stockman.

Also, did you do something about changing the size of the air hole?

[Ron99]

I actually have a reverse Durso at the bottom so air can escape. No back pressure in the line and it is not flushing or siphoning at all. It's not an air gurgling sound but a constant loud sound of the water flowing/rushing down the pipe. I do have an adjustable air valve in the cap at the top but changing that does nothing for the noise. It only changes the depth of water in the overflow box.

I have pretty much come to the conclusion that trying to run a single external Durso overflow from a bulkhead on the back of the tank near the top is extremely difficult and a poor choice. The best way to run overflows drilled at the top back of a tank is the herbie style. I am going to see if I can come up with a clever external herbie run off one bulkhead.

[golf nut]

It's rather difficult to solve a problem if we don't have all the facts, do you have pics?

[Ron99]

Hard to get pictures due to limited access but here's a diagram of how it is set up.

http://hotimg25.fotki.com/a/70_70/254_23/Overflow.jpg

[golf nut]

are there any reductions in the drain, at what level of the display is the water compared to the centerline of the drain bulkhead.

[Ron99]

There were no reductions in the drain, all 1.5 inch pipe. The centerline of the bulkhead is probably around 4 inches below the level of water in the tank.

In any case, it is academic now as I have solved the problem. I built a pseudo Herbie overflow with 2 1" drains coming off the 1.5 inch bulkhead using a T. It's angled so the majority of the flow goes down one side of the T and I have a ball valve on it to control the flow a la Herbie overflow. The higher end of the T is the emergency drain and dips around via 2 90 degree fittings. It is virtually silent now. Yay!!!!

I'll try to post some pics later.

[Ron99]

Finally getting around to posting a pic of my solution. It is a sort of Herbie going from a single 1.5" bulkhead to two 1" lines. It is nearly silent now and a huge difference from the constant sound of rushing water coming from the Durso.

http://hotimg23.fotki.com/a/70_70/254_23/Herbie.jpg