Silent and Failsafe Overflow System

[Reefer PT]

Internal to External overflow questions

Internal to External overflow questions

Just looking for confirmation. standard 120gal tank. Internal weir is C2C at 2" deep by 5" high. External Box I would like to do a 30"X 8"high by 3.5" deep box with 3 1" bulkheads in bottom of box and 1.25 pvc after bulkhead, BA drain. All glass using Momentive RTV silicone. For the holes between the boxes I found this drawing.

Now I was hoping to use the same hole saw as for the 1" bulkheads and only do 3-4 holes in the back of the tank.
1.Do you think using a 45mm hole and reducing the hole count would be detrimental or I should stick to the drawing and do a C2C external box too?
2. Do these holes b/t the internal and external need to have bulkheads on them to strengthen the glass?
3. Do the dimensions of the boxes seem right?
Thanks for your help.
Dave

 

[Skydivingcat]

So why exactly would my open stand pipe be siphoning and my siphon stand pipe just trickling? It really doesn't make much sense to me.

The open stand pipe shouldn't be siphoning since it has the tube sticking out the top of it, right?

All 3 exits in the sump are under water. Would that be a reason?

Your open channel is running in full siphon? If so it can not be open.

 

[Bent]

Your open channel is running in full siphon? If so it can not be open.

It's not full siphon, but it's fast. Maybe the line I have out of it is not big enough?

 

[Swope2bc]

It's not full siphon, but it's fast. Maybe the line I have out of it is not big enough?

Is your full siphon line wide open (the adjustment valve)? If so it would seem your flow is just a bit high for your plumbing. Perhaps neck back your return a bit.

 

[Bent]

Is your full siphon line wide open (the adjustment valve)? If so it would seem your flow is just a bit high for your plumbing. Perhaps neck back your return a bit.

That's a good idea, I've never tried turning down the return line. I'll give that a shot tonight.

 

[Skydivingcat]

That's a good idea, I've never tried turning down the return line. I'll give that a shot tonight.

Why would you want to reduce flow?

 

[Bent]

Why would you want to reduce flow?

Beats me but I'm willing to try anything at this point.

 

[Swope2bc]

Why would you want to reduce flow?

If his open line is flowing too much water then it is apparent that his full siphon is not keeping up with his return.

 

[Reefer PT]

anyone?

 

[Skydivingcat]

If his open line is flowing too much water then it is apparent that his full siphon is not keeping up with his return.

That seems like the backwards way to do it. Seems to me you should determine the flow required for your tank then size return and drain to meet those requirements.

I think in the three hundred or so pages in this thread this is the first time that the siphon drain could not keep up with the return flow.

 

[sleepydoc]

That's a good idea, I've never tried turning down the return line. I'll give that a shot tonight.

Replied to your other thread - What is your flow? My guess is your plumbing is the issue. How big is the vinyl tubing? A standard 1" pvc pipe can handle well in excess of 1500 gph when dropping 8', but the vinyl tubing is probalby throttling the system. At very least it's probalby causing problems with the open channel. For the system to start up properly, the water level needs to rise to the emeregency drain and stay up long enough for the siphon to purge the bubbles, then it will gradually drop down to steady state. this also depends on the open channel never coverting to a siphon.

Also, where do you have the valve for your siphon? If you have it up top, the negative pressure caused by the siphon can cause the viny tubing to collapse

 

[sleepydoc]

Just looking for confirmation. standard 120gal tank. Internal weir is C2C at 2" deep by 5" high. External Box I would like to do a 30"X 8"high by 3.5" deep box with 3 1" bulkheads in bottom of box and 1.25 pvc after bulkhead, BA drain. All glass using Momentive RTV silicone. For the holes between the boxes I found this drawing.

Now I was hoping to use the same hole saw as for the 1" bulkheads and only do 3-4 holes in the back of the tank.
1.Do you think using a 45mm hole and reducing the hole count would be detrimental or I should stick to the drawing and do a C2C external box too?
2. Do these holes b/t the internal and external need to have bulkheads on them to strengthen the glass?
3. Do the dimensions of the boxes seem right?
Thanks for your help.
Dave

Don't have time to write more, but in general:
It depends on your flow.
You don't have to have the external box be coast to coast, but you do need enough holes/area to allow the water to flow relatively unimpeded
The holes should be about at the same height as the water level which is set by your plumbing
Bulkheads do nothing to strengthen the glass
If yoour external box will be glass, make sure it is large enough to drill the holes without compromising the integrity.

 

[Bent]

Replied to your other thread - What is your flow? My guess is your plumbing is the issue. How big is the vinyl tubing? A standard 1" pvc pipe can handle well in excess of 1500 gph when dropping 8', but the vinyl tubing is probalby throttling the system. At very least it's probalby causing problems with the open channel. For the system to start up properly, the water level needs to rise to the emeregency drain and stay up long enough for the siphon to purge the bubbles, then it will gradually drop down to steady state. this also depends on the open channel never coverting to a siphon.

Also, where do you have the valve for your siphon? If you have it up top, the negative pressure caused by the siphon can cause the viny tubing to collapse

The vinyl tubing is also 1" ID. (Of course it is restricted a tad by the smaller nipples that you clamp the tubing too.) The open channel seems to be hogging all the flow. On start up, even with the siphon channel valve completely closed, the water level never makes it down the emergency pipe before the open channel just starts draining the box like mad.

Sigh. I'm going to have to replumb this aren't I?

 

[Reefer PT]

Don't have time to write more, but in general:
It depends on your flow. About 1000gph after head loss
You don't have to have the external box be coast to coast, but you do need enough holes/area to allow the water to flow relatively unimpededfor 45mm holes is 3 enough then? Or is 4 better?
The holes should be about at the same height as the water level which is set by your plumbing
Bulkheads do nothing to strengthen the glass
If yoour external box will be glass, make sure it is large enough to drill the holes without compromising the integrity. so is 3.5" too narrow then? From other posts on this thread that seemed to be a common dimension. Just want to know what is best..

 

[uncleof6]

Just looking for confirmation. standard 120gal tank. Internal weir is C2C at 2" deep by 5" high. External Box I would like to do a 30"X 8"high by 3.5" deep box with 3 1" bulkheads in bottom of box and 1.25 pvc after bulkhead, BA drain. All glass using Momentive RTV silicone. For the holes between the boxes I found this drawing.

Now I was hoping to use the same hole saw as for the 1" bulkheads and only do 3-4 holes in the back of the tank.
1.Do you think using a 45mm hole and reducing the hole count would be detrimental or I should stick to the drawing and do a C2C external box too?
2. Do these holes b/t the internal and external need to have bulkheads on them to strengthen the glass?
3. Do the dimensions of the boxes seem right?
Thanks for your help.
Dave

1) It depends. You want the internal and external to be one body of water. Hence no water level change, with water level at the center of the hole. The more "freely" the internal and external box communicate, the better off you will be. The implication is: you are not using the full diameter of the hole. Therefore what might appear to be overkill, may well be under kill.

2) You don't want any bulkheads in the holes. It will restrict the communication between the internal and external boxes. This is just one of the potential issues with the "ghost overflow" line of thought, that requires such bulkheads to hold everything together. One body of water, with waterline at the hole center line, is what you want.

3) The dimensions of the boxes, depends on the size of the pipe/fittings. It also depends on having the proper height differences between the inlets to the standpipes. Essentially, the tops of the down-turned elbows will be just a bit above the waterline. (slight variations.) So the final practical dimensions are up to you to determine, by measuring the plumbing etc, so everything ends up where it needs to be.

 

[uncleof6]

The vinyl tubing is also 1" ID. (Of course it is restricted a tad by the smaller nipples that you clamp the tubing too.) The open channel seems to be hogging all the flow. On start up, even with the siphon channel valve completely closed, the water level never makes it down the emergency pipe before the open channel just starts draining the box like mad.

Sigh. I'm going to have to replumb this aren't I?

There is a very short list of possibilities for the cause of your issue.

1) Your pipes are too deep in the sump. They need to be less than 1" below the surface of the sump. Any more than that creates the need for greater head pressure to purge the air out of the siphon line.

2) The air vent line is to low in the overflow box. If it is too low, the open channel will trip to siphon, before the siphon has a chance to purge the air. If the water level does not make it to the top of the dry emergency, there will not be enough head pressure to start the system, and hence the open channel takes all the flow. That is the acid test. The air vent line inlet needs to be above the inlet to the dry emergency,

3) Horizontal runs in the plumbing can cause the siphon to air lock, and the open channel takes all the flow.


3) Less common problem, is the bulkheads being too large for the flow rate. If you have 1.5" bulkheads, and 600gph (just a random low flow number) the system will not start, and the open channel takes all the flow.

4) Vinyl tubing is a poor material to use. The fittings are restrictive, just for one. If you need "flexibility" then spa-flex is the material to use. Quite honestly, there should be no need for flexibility, as a little thought can usually solve most routing problems.

Invariably, with start up issues, it is a problem with the implementation. How it was put together. Using a fine tooth comb, and going over the implementation, will solve the issue.

**********************************************************

Topic Change:

In this post http://reefcentral.com/forums/showpost.php?p=23863094&postcount=8530, (no reflection on the person that posted it) the dry emergency is way to low in relation to the other two standpipes, and the water level has no place to rise. It is a certain recipe for a failed system. I have stressed this in the past, but I will go back to it again: you cannot stuff this system in a tiny box, and expect it to work the way it is supposed to. It may drain water, but it will not work the way it is supposed to. I have run too many tests on "jamming" it in small boxes. This system functions on head pressure, not miracles, and the setup in the cited post, will not get any head pressure on the siphon.If you look back a ways in this thread, I posted a link to a video that shows how high the water level needs to get to start the siphon, the right way.

I am not enthralled with the internal/external concept, and I built it over 5 years ago. It works well, but was a waste of time. I don't think the "need for minimal footprint" should outweigh the need for performance, and the "small" internal/external setups (aka "ghost overflow") are self defeating, and a considerable step backwards, performance wise. What should come first is the needs of the system, not aesthetics; the "ghost overflow" is no more aesthetic than an original design BA, but from what I have seen, the original design BA out performs it.

 

[Reefer PT]

I am not enthralled with the internal/external concept, and I built it over 5 years ago. It works well, but was a waste of time. I don't think the "need for minimal footprint" should outweigh the need for performance, and the "small" internal/external setups (aka "ghost overflow") are self defeating, and a considerable step backwards, performance wise. What should come first is the needs of the system, not aesthetics; the "ghost overflow" is no more aesthetic than an original design BA, but from what I have seen, the original design BA out performs it.

Maybe a 2 new sticky threads should be started with one being a proper internal only BA setup and one for Internal/external setups. As I made an honest attempt to read through this monster of a thread I came to the conclusion (maybe falsely) that the internal/external overflow was "the best way." Uncle, thank you for so much time you put into this thread! I just feel that it has become information overload as so many have tried to modify the system and have sought advise on how to deal with the problems. I feel there just needs to be a simple HOW -TO thread and if someone varies the system, they should seek help on a separate thread.
Dave

 

[Adamc1303]

Wondering if anyone has tried this before. I currently run a Bean Animal drain. I wanted to try to get more turn over in the tank. If I add a gate valve to the secondary drain and turn it into Herbie would there be any reason that comes to mind that it wouldn't work? Once I know that more turnover in the tank would remedy some of the issues I am having then I would consider re-drilling 3 more holes to setup another full Bean Animal system. I just don't want to do it if there is any reason that I am not thinking of at the moment that will cause it to not work properly.


Thanks,

Adam

 

[Bent]

Wondering if anyone has tried this before. I currently run a Bean Animal drain. I wanted to try to get more turn over in the tank. If I add a gate valve to the secondary drain and turn it into Herbie would there be any reason that comes to mind that it wouldn't work? Once I know that more turnover in the tank would remedy some of the issues I am having then I would consider re-drilling 3 more holes to setup another full Bean Animal system. I just don't want to do it if there is any reason that I am not thinking of at the moment that will cause it to not work properly.


Thanks,

Adam

I put a ball valve on my open channel and it's the only way I could get my application to work.

 

[StrangeDejavu]

I'll be drilling my tank for the external Bean design this week, and was hoping someone could answer two quick questions for me:

1) Will two holes in the tank draining into the box be enough or should I have three?
2) Is there a set size for dimensions of the box? Or can I make it whatever size I want?

Thanks!