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I tried the elbow and if I increase the flow I hear the same noise in the secondary as without the elbow, example if I add a powerhead sometimes more water goes through the overflow like a wavemaker example or high flow uptop random and I heard water trickling “annoying” noise in secondary with the elbow + rodi tubing in the hole vs without elbow same noise, what am I doing wrong with the elbow to have it muffled?Explained in detail just a few posts back.
Personally, I wouldn't use the elbows on any of the drains.Hello guys,
I am getting ready to setup the new plumbing for my running DT. I have purchased the Modular Marine 800GPH Bean Animal style overflow box. The issue I'm having while testing the setup dry, is that I cannot fit 2x 90 elbows back to back for 2 of the 3 pipes inside the box. I can only fit one elbow, and I'm wondering if that will be enough to have a full syphon with no noise as all of the bean animal setup I've seen, have 2x elbow creating a 'U' shape inside the box.
Can someone please let me know if just one 90 elbow on two of the 3 pipes will suffice for a silent complete drain?
Hello guys,
I am getting ready to setup the new plumbing for my running DT. I have purchased the Modular Marine 800GPH Bean Animal style overflow box. The issue I'm having while testing the setup dry, is that I cannot fit 2x 90 elbows back to back for 2 of the 3 pipes inside the box. I can only fit one elbow, and I'm wondering if that will be enough to have a full syphon with no noise as all of the bean animal setup I've seen, have 2x elbow creating a 'U' shape inside the box.
Can someone please let me know if just one 90 elbow on two of the 3 pipes will suffice for a silent complete drain?
Personally, I wouldn't use the elbows on any of the drains.

You dont need or want an elbow on the siphon "main" drain. There should be no reason for it and may interfere with operation. Water level should be set with the secondary drain so the siphon "main" drain stays submerged and as long as flow continues with in a certain amount will keep the water level above the main drain continuing its ability to keep a siphon.
Good points. The secondary drain may need to be a bit "taller". In this case that elbow may be needed. Most of my tanks are herbie style but one is Bean animal having an elbow on the siphon caused nothing but issues for me taking it off it worked as it should right away. My secondary drain on that tank is only maybe an inch below the emergency drain. I just used the pipes that came with the overflow box, 3 sizes and the emergency was red other two were black. Red one sits about an inch below the weir, secondary is maybe two inches below and the siphon is only maybe three inches long.Think Bean's explained it about three times, but with that distance between your primary and secondary drain height I suspect you need that elbow on the primary. Otherwise the water level needed to achieve full siphon without a vortex will be near your secondary drain level, possibly causing periodic breaks in the siphon and air sucking noise with variations in flow. Hard to tell in a photo though.
Make sure you have holes drilled in the tops of the elbows to allow air to escape as the box fills.
Maybe somebody could ask the guy who designed the systemYou dont need or want an elbow on the siphon "main" drain. There should be no reason for it and may interfere with operation.

That is not how the system works.Water level should be set with the secondary drain so the siphon "main" drain stays submerged and as long as flow continues with in a certain amount will keep the water level above the main drain continuing its ability to keep a siphon.
adding the elbow setup likely caused the siphon standpipes weir height to be higher than the open channel. This will not work.Bean animal having an elbow on the siphon caused nothing but issues for me taking it off it worked as it should right away.
I'm getting different opinions and I'm confused. To check if I'm following, raise the emergency pipe about an inch below the rim. The main drain (lowest one), one elbow, two elbows, no elbow? Lastly, for the secondary drain, one elbow, two elbows, or no elbow?adding the elbow setup likely caused the siphon standpipes weir height to be higher than the open channel. This will not work.
Also, the emergency can be raised higher if needed. It does not need to be below the weir height, but does need to be below the trim or true f,old height with enough headroom to kick in with the primary and secondary closed with the return pump running.
Lastly, depending on flow, the smaller standpipe would likely work as the siphon, leaving the larger pipes for secondary (quieter) and emergency.
The system (as designed) will work with the siphon (what people are calling the main) and the open channel (what people are calling the secondary) at the same height. Lowering the siphon can aid in it starting. However, the actual water level in the overflow box is adjusted by the flow rate of the siphon standpipe, not its height or the height of the open channel. The idea is to set the valve on the siphon standpipe to force a portion of the flow into the open channel. This is what keep the system balanced. If flow increases a bit, the open channel handles a bit more (as does the siphon due to increased head). If flow drops a bit, the flow slows in the open channel, and to an extend in the siphon due to decreased head. They interact with each other to autotune and prevent air from being sucked in or flow from backing up and flooding.I'm getting different opinions and I'm confused. To check if I'm following, raise the emergency pipe about an inch below the rim. The main drain (lowest one), one elbow, two elbows, no elbow? Lastly, for the secondary drain, one elbow, two elbows, or no elbow?
exactlyHi Bean,
This is my current setup:
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I tried doing this, but there was a lot of noise coming from the secondary:
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In my system, the water level needs to be maintained just below the secondary drain to avoid activating it and generating excess noise.
What did I do wrong in the second picture ?
Thanks. I’ll try it again. Is this size of the hole important? Maybe it was too small when I did it a few years ago?exactly
The size of the hole needs to be large enough to prevent a partial siphon from forming. 1/4" is fine.Thanks. I’ll try it again. Is this size of the hole important? Maybe it was too small when I did it a few years ago?
