Shadow Overflow Noise

[tom39]

I just finished installing a 16" Shadow overflow on my 150DD. Return volume is only about 1100-1200gph but I am still having issues with a waterfall noise coming from the inside weir box. Has anyone encountered this issue and if so, how have you addressed it?
Thanks,
Tom

 

[Berlibee]

Adjust your return valve, start closing it slowly until the noise is gone.

 

[tom39]

The noise is not from the plumbing. The siphon is spot on and runs silent. The noise I am referring to is coming from a water fall effect as water flows through the weir teeth and falls within the interior box.

 

[M3ace9]

You need to raise your secondary full siphon so that the water flows strait across instead of down into the box

 

[KJAG]

You need to raise your secondary full siphon so that the water flows strait across instead of down into the box

"Secondary full siphon?" Please elaborate.

 

[M3ace9]

"Secondary full siphon?" Please elaborate.

The second drain that will become a full siphon in the case that the first one gets clogged.

 

[KJAG]

The second drain that will become a full siphon in the case that the first one gets clogged.

Right. That's the open channel. It's not a siphon. If it's plumbed as a Bean.

 

[tom39]

I have the water in the exterior box set as high as will allow without risking an overflow if the weir teeth are removed or fall out while the return is running. Water enters the exterior box at a height of about half of the bulkhead fittings. Additionally, the secondary cannot be raised any more than it already is or it will reside outside of the exterior box and the cover will not fit as it should.

 

[M3ace9]

Right. That's the open channel. It's not a siphon. If it's plumbed as a Bean.

Right. That's the open channel. It's not a siphon. If it's plumbed as a Bean.

Right the open channel that is an open channel until it is needed and becomes a full siphon which would make it a full siphon.

 

[M3ace9]

The water in the exterior box is as high as will allow without risking an overflow. Thus the secondary cannot be raised any more than it already is or it will reside outside of the exterior box and the cover will not fit as it should.

If the water level is high and the box and you are not getting a waterfall into it then you may want to look at your powerhead setup. I found that any turbulence near the teeth or the box will create an echoe within it. I fixed this issue by moving my power heads slightly away from the box

 

[KJAG]

Right the open channel that is an open channel until it is needed and becomes a full siphon which would make it a full siphon.

Indeed. But we don't call the emergency channel the third siphon. That's all. See your first post. Was just curious what you were referring to which is why I asked to elaborate.

 

[justingraham]

I have the same problem as u what I did was remove the second u fitting on the secondary line to make the lid close. When I get it dead silent water drips out of the back box and the water is over the emergency pipe or third syphon as referred to earlier. No it's not power heads either. And the noise is coming from my weir not my pipes side question with the lid off does the back box bow outwards? I'm glad someone has the same problem so hopefully we can figure this out together I believe I'm running around 1100-1200 gph as well. I feel ur pain please anyone who can help @hybridazn what is the sponge trick u said u did with the glass overflows?

Please help me and the op make are tanks silent like everybody else (it is not the piping so please don't tell us we don't have it plumbed right cause I do in fact I have it to where the full syphon is moving all 1200 gallons and no water is going down the secondary with no avail the only way to silence it is to raise the water above the bulkheads which spills water on the ground)

 

[hybridazn]

I used enkamat to silence the overflow on my old frag system and it worked well. Have you guys tried slowing the flow thru the overflow box to see if that helps? I know the shadow is rated for 1500gph but being on average 2-300gph below that I think you guys are pushing it a bit.

Enkamat is what ppl use to modify skimmer impellers for the mesh mod

Also, how far below the water level are the pipes in the sump? The full siphon pipe needs to only be an inch or 2 below, any lower and it is difficult for it to start the full siphon. Take a piece of airline tubing and stick it up into the full siphon pipe and see if air comes out of the tubing, if it does suck on the tubing to pull the air out and start the siphon if that's the case.

 

[tom39]

I used enkamat to silence the overflow on my old frag system and it worked well. Have you guys tried slowing the flow thru the overflow box to see if that helps? I know the shadow is rated for 1500gph but being on average 2-300gph below that I think you guys are pushing it a bit.

Enkamat is what ppl use to modify skimmer impellers for the mesh mod

Also, how far below the water level are the pipes in the sump? The full siphon pipe needs to only be an inch or 2 below, any lower and it is difficult for it to start the full siphon. Take a piece of airline tubing and stick it up into the full siphon pipe and see if air comes out of the tubing, if it does suck on the tubing to pull the air out and start the siphon if that's the case.

I like the enkamat idea and will give it a try. Last evening I tried using plastic canvas and was able to reduce the noise by 70%. At this point it is tolerable but further reduction in the noise would be even better.
As for the length or depth of the siphon line and the secondary line in the sump. I have those set to about 1/2" below the water surface of the sump.
In regards to flow, I think that you are correct that the volume I am pushing through the overflow exceeds the products capability to remain quiet as I am predicting that I have about 1100-1200gph (my return pump is a Sicce 5.0) with 1.5" plumbing. At this flow rate I am achieving full siphon within 60sec and any remaining air is purged within 5min; which I consider reasonable. I do however feel that a reduction in the flow rate may cause issues with achieving full siphon within a reasonable period of time if using 1.5" plumbing. If I had to do over knowing what I know now, I would have reduced the plumbing size to 1.25" and aimed for a 900-1000gph flow rate.

Thank you for your help and advice and I will provide an update on my progress.

Tom

 

[tom39]

If the water level is high and the box and you are not getting a waterfall into it then you may want to look at your powerhead setup. I found that any turbulence near the teeth or the box will create an echoe within it. I fixed this issue by moving my power heads slightly away from the box

At this point I am freshwater testing without the use of powerheads.

Tom

 

[needbiggertanks]

Stupid question, (i just purchased this) in the back box, did you use the pipe lengths that the instructions specified? I want to avoid this issue in my new build.

The 7", 2.5", and 3.25" ?

 

[needbiggertanks]

By the way, i understand thats not necessarily your issue, im just asking because of the potential for the water to overflow the outer box

 

[tom39]

Stupid question, (i just purchased this) in the back box, did you use the pipe lengths that the instructions specified? I want to avoid this issue in my new build.

The 7", 2.5", and 3.25" ?

I didn't actually. I custom fit my pipes so that the inlet of the main siphon u-tube was 3/4" off the bottom of the outside box, the secondary u-tube was set high enough to fully submerge the main siphon u-tube and the emergency drain was set at the same height as the highest point/apex of the secondary u-tube.
I am still running my freshwater test and making some fine tuning adjustments but will certainly post all of my findings when I am finished tuning.

 

[justingraham]

I did the recommended heights and it was still noise actually way noiseier.

I think it just comes down to flow if ur going to have anything above 1000gph the front weir will be loud

 

[needbiggertanks]

Thanks a lot.