Silent and Failsafe Overflow System

Good info Unc. That is one thing I haven't taken into account much in the past w/r the the "coast to coast" / still waters.

And no offense to the RC people who made the calculator, but it is worthless, at least from my perspective. I know that flow is a function of the length and type of overflow (slotted v weir) and of water height, and that calculator does not account for any of that IMO. Using the equation above that I just posted would result in a much better number.

Add (had to run an errand): They just have you insert a number for GPH and then give you this arbitrary number for the length of the overflow, but don't tell you if that is with teeth, without teeth, and if there are teeth, how many and of what width and spacing, and what depth they need to be (i.e. what the water level going through the teeth will be). All of these are factors.

I put in 700 GPH and it spits out 11 linear inch overflow. That's it. I would rather have the calculator with the other way, where you put in all the parameters and it tells you how much flow you can get out of a given overflow.
 
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So after months of planning, this is my first full day with the BeanAnimal on my 180 gal. And it is stable and quiet...but not quite silent like some of the videos show. I can hear the open channel pipe a little and small bubbles are always coming out of the open channel even after hours of operation. I cannot increase the flow through the siphon, as then the water coming INTO the overflow splashes....and my water level inside the overflow is not yet "half-way-up-the-elbow" as Bean recommends. What do you think if I place an elbow where the open channel hits the water level in the sump. Would that quiet it down.

it's really not bad and I can live with it (certainly quieter than my LAST overflow) but it is not silent as some of the videos show....any ideas?
 
Yes, pics. Also you may have to wait a few days to a week for your pipes to develop a slime coating which will calm the bubbles down, at least that's what I noticed.
 
I'm hoping it's the slime coat thing....I am using 1.5 in pipe and it is fairly straight path. I have only 2 45-degree elbows to get to the sump. I can actually tune it so that NOTHING goes through the open channel and all flow is through the siphon...but then I get splashing from the tank into the overflow and I figure that configuration is not that stable. I will try to get pictures.
 
JTL said:
Why would the 1" plumbing make a difference? As far as trapping air goes I can remove part of the pipe above the water line and it still doesn't siphon and the open channel has a lot of flow even though the pipe is below the water line in the sump.
Click to expand...

AsI mentioned, there are several areas in which your setup deviates from the original specification and therefore the fluid dynamics are also changed.

First of all, the "open channel" is just that, a pipe that allows water to flow in an open channel manner. That means the entire length of pipe is open to the surrounding atmosphere and "trapped" air is not present to effect the flow by creating turbulance and a siphon can not form because of the open air path. The horizontal run in your setup forces air to become trapped and/or depending on flow volume and rate allows a siphon to form.

Given two pipes with the same flow, imagine a large horizontal pipe HALF full) where air is present along the entire length of hte pipe run. Now shove that SAME flow through a pipe that has HALF the area. The pipe will now run FULL or ALMOST FULL. This will either create a siphon and greatly increase the flow rate, or trap pockets of air and creature turbulance that greatly reeduces the flow rate.

My overflow was designed to make use of BOTH open channel flow and SIPHON flow to avoid the situation described above. By downsizing your pipe AND adding a horizontal run, you have created a situation where the open channel is not functioning as an open channel and the siphon is airlocking because the open channel has less resistance and begins to siphon, as it can not operate in "open channel" flow mode due to the horizontal run and smaller diameter pipe.

1) The pipes likely need to be upsized.
2) The control valve needs to be at the end of the pipe
3) The pipes (at least the open channel) need to be sloped at a decent grade, not "horizontal". To that end, the larger the diameter of the horizontal portion of the open channel, the better.
 
Floyd R Turbo said:
Good info Unc. That is one thing I haven't taken into account much in the past w/r the the "coast to coast" / still waters.

And no offense to the RC people who made the calculator, but it is worthless, at least from my perspective. I know that flow is a function of the length and type of overflow (slotted v weir) and of water height, and that calculator does not account for any of that IMO. Using the equation above that I just posted would result in a much better number.

Add (had to run an errand): They just have you insert a number for GPH and then give you this arbitrary number for the length of the overflow, but don't tell you if that is with teeth, without teeth, and if there are teeth, how many and of what width and spacing, and what depth they need to be (i.e. what the water level going through the teeth will be). All of these are factors.

I put in 700 GPH and it spits out 11 linear inch overflow. That's it. I would rather have the calculator with the other way, where you put in all the parameters and it tells you how much flow you can get out of a given overflow.
Click to expand...

The RC calculator appears to simply give a rough estimate of the total overflow linear length needed for the minumum surface skimming for a given flow rate. The length is the total weir length, not including teeth.

That is, if it spits out 11" and you have .5" wide teeth with .5" wide slots between them, then you would need a TOTAL overlow length of 22". That would give you roughly 11" of open space (the weir). That said, each tooth causes turbulance where the surface tension of the water is attracted to the vertical tooth walls. This reduces velocity fairly significantly and therefore increases depth at the weir(s) and in turn reduces surface skimming efficiency.

As the cacluation are rather complex, the RC calculator just spits out a rather generic minumum number. More teeth mean less efficiency and that means an even longer weir.

Hope that makes some sense....
 
Bean, can you please tell me if you think this will work or do a need to flip the sump?
Bulkheads are 1” and drilled 1 ¾” holes. Siphon and open channel is 1 ½” and the emergency drain is 1”. Assuming the open channel first, about an 18” long horizontal run. Then the siphon about a 12” long horizontal run.

120TANKOVERVIEW.jpg~original
 
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The siphon should be the 1" and the OC and Emergency the 1.5". THe open channel should be the shortest run, the emergency likely longest.

What is your proposed flow rate? Why the long horizontal runs and not just end them all at the edge of the sump.
 
Floyd R Turbo said:
I would opt to make the external box deeper. The tank I run the BA on has the overflow on the end, and maybe that's part of it, but the weir dumps about 1" down into the box (16" wide 3000 GPH) and I needed something inserted into the box to 'break the fall' to prevent air from getting sucked into the siphon. Maybe 8" deep.

Also is this an acrylic tank? off topic, but cutting the back of the tank like that and disconnecting it from the euro (which is way, way to narrow) mean your external box is structural and needs to be pretty thick.

And for what it's worth, I would go to Miracles before Reef Saavy any day.
Click to expand...


Better safe than sorry on the overflow depth. It just gives me more adjustment room by going 8", so if the aquarium builder is okay with the extra weight on the back, that's the way I'll go.

Tank is tentatively 1/2" glass. I've struggled with the glass versus acrylic question, but that's another story for another thread :). I plan on starting a build thread once a nail down a couple more details.

Any other thoughts on the overflow? 1" bulkheads seem reasonable for a 100 gallon tank? Also, one return or two?

Thanks for the help!

Bill
 
BeanAnimal said:
The siphon should be the 1" and the OC and Emergency the 1.5". THe open channel should be the shortest run, the emergency likely longest.

What is your proposed flow rate? Why the long horizontal runs and not just end them all at the edge of the sump.
Click to expand...

The reason for the long run instead of dropping straight down, Well… while reading another post they said they had noise and it went away when adding length to the horizontal run. On my temporary 75DT I had a HOB OF with a durso style drain and it had some noise at the sump it had an off set of about 4” on a 20” fall. When I add the temporary remote sump behind the fridge this added horizontal run both from the HOB OF and from the remote sump to the sump. This has made the sound so much quieter. I still hear it some in in the remote sump but not so much in the sump, now.

I would have made all same size but limited space on the 1 drain. As for the rate, when using the flow calculator it says:

For ¾ return: 9.38 feet of head pressure, or 4.05 PSI. with a flow rate of 465 GPH.
For 1” return: 7.74 feet of head pressure, or 3.35 PSI. with a flow rate of 593 GPH

I have about 300 gph on my 75 on ¾” now. I have 2 double power heads for the 120. I only have one of them in the 75 at the moment. I have not decided on the return yet. I did buy a ¾” y and end pieces of the lock line to have two ¾” adjustable returns.

I also will be use acrylic for the overflow. I’m hoping the will work. It has about 2* angled (sloped) on the bottom to cut any hanging air bubbles and about a 2* fall on the overflow part to hopefully not let the water fall so it will roll or slide in. it has a 7/16 opening that I still have to round over the edges. Hopefully this will keep critters out but not stop water like teeth do. It will have two 10 ½ openings so 21” total I think the water runs about ¼ thick on my current HOB OF box. If any of this is wrong please correct me now. And thanx again for the help

DSC01716.jpg~original


downsized_0204022213.jpg~original


0211022211.jpg~original
 
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Hey Bean,

You said "If you are concerned about the siphon starting, then you can place the open channel standpipe bulkhead slightly higher (1/2" or so) than the siphon standpipe bulkhead."

Is this necessary? Do you recommend this on a new set up? I see that all the bulkheads in your system are at the same height.
 
I have never seen a need to raise the open channel. Most starting issues can ultimately be traced to a modification or misinterpretation of the original basic design.
 
roczero said:
Hey Bean,

You said "If you are concerned about the siphon starting, then you can place the open channel standpipe bulkhead slightly higher (1/2" or so) than the siphon standpipe bulkhead."

Is this necessary? Do you recommend this on a new set up? I see that all the bulkheads in your system are at the same height.
Click to expand...

As Jim just mentioned, the system works as designed. If you build it as designed then you don't need to raise it. However, it is an option (to riase the OC weir) when the design is not followed and/or other factors come into plate (dump boxes, etc).
 
BeanAnimal said:
AsI mentioned, there are several areas in which your setup deviates from the original specification and therefore the fluid dynamics are also changed.

First of all, the "open channel" is just that, a pipe that allows water to flow in an open channel manner. That means the entire length of pipe is open to the surrounding atmosphere and "trapped" air is not present to effect the flow by creating turbulance and a siphon can not form because of the open air path. The horizontal run in your setup forces air to become trapped and/or depending on flow volume and rate allows a siphon to form.

Given two pipes with the same flow, imagine a large horizontal pipe HALF full) where air is present along the entire length of hte pipe run. Now shove that SAME flow through a pipe that has HALF the area. The pipe will now run FULL or ALMOST FULL. This will either create a siphon and greatly increase the flow rate, or trap pockets of air and creature turbulance that greatly reeduces the flow rate.

My overflow was designed to make use of BOTH open channel flow and SIPHON flow to avoid the situation described above. By downsizing your pipe AND adding a horizontal run, you have created a situation where the open channel is not functioning as an open channel and the siphon is airlocking because the open channel has less resistance and begins to siphon, as it can not operate in "open channel" flow mode due to the horizontal run and smaller diameter pipe.

1) The pipes likely need to be upsized.
2) The control valve needs to be at the end of the pipe
3) The pipes (at least the open channel) need to be sloped at a decent grade, not "horizontal". To that end, the larger the diameter of the horizontal portion of the open channel, the better.
Click to expand...

Since I posted this question I made some mods and it works pretty good. I was able to almost eliminate the the open channel horizontal run and I shortened and added some slope to the full siphon pipe. Thanks for the advice.
 
Curious if this can be done in an external overflow?
Does the piping have to be short as I have mine run the length of the aquarium to the sump
I have (3) 1.5" bulkheads but mainly concerned if I "need" the valve of the full siphon line or not. What exactly is the purpose of it? Is it merely to adjust the amount of siphon?
 
eagle9252 said:
The reason for the long run instead of dropping straight down, Well"¦ while reading another post they said they had noise and it went away when adding length to the horizontal run. On my temporary 75DT I had a HOB OF with a durso style drain and it had some noise at the sump it had an off set of about 4" on a 20" fall. When I add the temporary remote sump behind the fridge this added horizontal run both from the HOB OF and from the remote sump to the sump. This has made the sound so much quieter. I still hear it some in in the remote sump but not so much in the sump, now.

I would have made all same size but limited space on the 1 drain. As for the rate, when using the flow calculator it says:

For ¾ return: 9.38 feet of head pressure, or 4.05 PSI. with a flow rate of 465 GPH.
For 1" return: 7.74 feet of head pressure, or 3.35 PSI. with a flow rate of 593 GPH

I have about 300 gph on my 75 on ¾" now. I have 2 double power heads for the 120. I only have one of them in the 75 at the moment. I have not decided on the return yet. I did buy a ¾" y and end pieces of the lock line to have two ¾" adjustable returns.

I also will be use acrylic for the overflow. I'm hoping the will work. It has about 2* angled (sloped) on the bottom to cut any hanging air bubbles and about a 2* fall on the overflow part to hopefully not let the water fall so it will roll or slide in. it has a 7/16 opening that I still have to round over the edges. Hopefully this will keep critters out but not stop water like teeth do. It will have two 10 ½ openings so 21" total I think the water runs about ¼ thick on my current HOB OF box. If any of this is wrong please correct me now. And thanx again for the help
Click to expand...


Bean, after reading and rereading I'm confused.
Why did you say that the full siphon should be the 1" and not the 1-1/2? I was thinking that the emergency should be the 1" and the OC and full siphon 1-1/2" I can plumb either way just asking.

Also you said to drop the OC straight down. Should I not have any horizontal run in it? When I had my first HOB OF it was setup as the OC and it was noisy dropping in the sump. When I added the temporary remote sump I added horizontal runs about 18". This made it a lot quieter but it still has some noise, more than I would like to have.
 
The open channel should always be the largest diamter, followed by the emergency, as the emergency MUST be able to carry the full system flow. In most cases, the 1" will be sufficient to handle the full flow (under siphon) of the return pump. If it is NOT, then there really is no place for 1" in the system.

In the scenario where the system only has modest flow, the siphon valve may be closed significantly, and in this case the 1" emergency is likely enough. That said, it still makes more sense to dedicate the smaller standpipe to the siphon and the larger to the emergency.

Remember, this design was published as a ONE SIZE fits all system that can be used AS IS to accomodate just about ANY size tank. In that spirit, some of the parameters leave a lot of headroom on smaller systems.

A slight cant (lean) and/or a 45 bend or two in the OC will help to keep the water from dropping and splashing. Horizontal runs can create issues where the water backups and and causes pulsation and gurgling. It may or may not, but again (as we keep mentioning) the original plan does not account for such variables. When you introduce them, you will have to make adjustments to keep the system working as expected. For most folks, this means a noisy system and complaints that the design does not work...
 
I understand. In my original temporary setup I had only 1 OC setup. It dropped almost straight down. It had two 45*s which had about a 4” offset.
 
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