BeAn Over flow system

[msudvm97]

I was looking into setting up a BeAn Overflow system for either a 150 - 180 gal. tank (not yet set up or purchased.)
Questions:
Regarding the Two siphons that are in the over flow that have their 90 degree elbow facing in the water ( I believe they are called the ' siphon' and the 'open channel standpipe'.
- Do you have these holes drilled in the tank at the same level ?
- How far from the top of the tank to you go down ( example; is there something like..the top of the
drilled hole should be 3 " from the top ) ?
- Any preference for the size of the PCV tubing ?
- Do they enter into the water of the over flow box at the same level ?
- It appears that all three pipes flow straight into the sump - I read that it is best to only have them be
about 1" below the surface of the sump's water level...you agree ?
- The 'L" shaped over flow box - Made of acrylic ?
- Do you have slatted entrance into the over flow box or just free flow in ?
- Are you drilling these tanks and gluing the 'L" shaped over flow or are you having it done ?
- How long is the over flow box , 75 % of the tank size ?
- Do you drill the three holes in one side of the tank or better in the middle ?

- Recommended hole diameter of hole
- If I were to put the Sump in my basement, the out flow tubes would go down from my
tank into the floor through a crawl space, then they would travel horizontally for
several feet before turning downward several feet again and finially into a ~ 200 gal
sump. Do you think this would pose a problem ?

- Where do you have the in-tank overflow box made ?
- If I bumped this up to a 180 to 240 gal. tank how big do you think I should make the
holes...1 inch ?

If the tank is 6 or 8 feet long.......would you put more then one group of three stand pipes (a group of three standpipes is defined as; one Emergency Standpipe, One Full Siphon Standpipe and One Open Channel Standpipe) into the over flow box (thus yeilding 6 or 9 tubes going into the Sump from the tank)?

Thank you for your time
Steve

 

[mojo]

I have never used one but many here have. I am sure someone will chime in soon.

 

[Hahnmeister]

Lets start with this... you dont need three pipes as two can do everything the three can do.

If it was just two pipes, what would be the largest pipes you could have drilled?

How much flow are you looking to have through this overflow?

How long of an overflow can you put in? How many linear inches would be a good figure to tell.

Then we can predict flow rates, pipe numbers/sizes, etc.

 

[msudvm97]

I read that the bulk heads were 1.5 inches and the pipes were 1 inch....? (why?)
The overflow would be a coast/coast internal box running the length of the tank.
The sump will be in the basement, then about 14 foot vertical drop and several feet horizontal.
The sump will be at least 100 gal/ house the protein skimmer/ refugium

 

[Russter]

The third pipe is used as an emergency in case the other two pipes fail. here are some pictures of one I had setup on a 90 gal

To answer your questions:
-Holes are drilled at the same level in the tank
-holes should be drilled a safe distance from the edge. This depends on the size of the bulkheads.
-1.5" bulkheads provide enough flow for most tanks.
-They enter the water of the overflow at the same level. should be close to the bottom of the overflow if possible to discourage entry of snails.
-agree, although you may have to extend the length of the open channel a bit deeper to encourage the syphon channel to fill first.
-depending on what your tank is made of, overflow can be made of same material...glass or acrylic.
-do not use slats/teeth for the overflow. you want a thin layer of water to cascade over the weir.
-yes, drill the tank and glue/silicone the overflow in.
-go coast to coast on the overflow length unless you want room at the sides to run your return pipes.
-doesn't really matter if where you drill the holes. whatever works best for your sump
-hole diameter depends on bulkhead size. go with 1.5" or 2" bulkheads
-the couple of feet of horizontal run should not cause any problems
-I got mine cut at a local glass shop. they cut the two pieces and I siliconed them together in the tank
-with a six or nine foot tank, you should have enough flow with one set of three pipes.

Here is a pic that you can see the level of the water over the overflow in a 20 gal

 

[Aquaph8]

I know your doing an internal coast to coast but just to show another way of doing it. I went with 1.5 pipe throughout. Holes are drilled in the bottom of the overflow box. Probably not what your looking for but maybe gives a little different angle to view it from. goodluck.

[/IMG]

 

[Hahnmeister]

The third pipe is redundant since the second pipe is there as a backup already and really cant fail anyways. You are usually taking 100 percent of the flow through the primary pipe after all... the secondary is a backup to that.

 

[msudvm97]

Is there any difference in terms of effeciency: an internal box vereses an external box ?
To me it seemed that the internal box was 'safer' - less likely for leaks, because with an external boxthere seems to be more potential for leaks. So I guess that begs the questions what are the pros / cons of an internal box verses an external box ?
External box: Pros: - more room in the tank
- Only have to 'cut the back down' to get the water flow over it / not cutting holes in the tank
Cons: - More potential for leaks if there is any issues with the seal

Internal Box: Pros: - No leak issues if the seal on the box is not good
Cons: - Have to cut 3 holes in the back of the tank
- Will take up a small amount of space in the tank
- Greater potential for dead spots

Am I missing anything else ? I am open to either option, if one seems to be clearly better.

Thank you for your time
Steve

Thank you for your time
Steve

 

[Russter]

The third pipe is redundant since the second pipe is there as a backup already and really cant fail anyways. You are usually taking 100 percent of the flow through the primary pipe after all... the secondary is a backup to that.

That is why the third pipe is called the "emergency pipe". In case of that. It is a safety measure that usually kicks in during start-up while the air is being purged from the siphon pipe. With the OP's long run to the basement (meaning lots of air in pipe), this will be extremely important to have to prevent any floods in case of power outage. That is the beauty of this system. The three pipes provide triple redundancy to prevent overflows and it is dead silent. You are defeating the purpose of this system if you don't install the third pipe and seeing as space is not an issue here, there would be no valid reason not to.

Is there any difference in terms of effeciency: an internal box vereses an external box ?
To me it seemed that the internal box was 'safer' - less likely for leaks, because with an external boxthere seems to be more potential for leaks. So I guess that begs the questions what are the pros / cons of an internal box verses an external box ?
External box: Pros: - more room in the tank
- Only have to 'cut the back down' to get the water flow over it / not cutting holes in the tank
Cons: - More potential for leaks if there is any issues with the seal

Internal Box: Pros: - No leak issues if the seal on the box is not good
Cons: - Have to cut 3 holes in the back of the tank
- Will take up a small amount of space in the tank
- Greater potential for dead spots

Am I missing anything else ? I am open to either option, if one seems to be clearly better.

Thank you for your time
Steve

Thank you for your time
Steve

All of your pros and cons are right on the money. Another pro for internal is that it is easier to drill three holes than to cut down the back pane for a weir in a glass aquarium.

 

[Aquaph8]

I agree with Russter

 

[Hahnmeister]

That is why the third pipe is called the "emergency pipe". In case of that. It is a safety measure that usually kicks in during start-up while the air is being purged from the siphon pipe. With the OP's long run to the basement (meaning lots of air in pipe), this will be extremely important to have to prevent any floods in case of power outage. That is the beauty of this system. The three pipes provide triple redundancy to prevent overflows and it is dead silent. You are defeating the purpose of this system if you don't install the third pipe and seeing as space is not an issue here, there would be no valid reason not to.


All of your pros and cons are right on the money. Another pro for internal is that it is easier to drill three holes than to cut down the back pane for a weir in a glass aquarium.

By that logic, why not just add a fourth pipe as a triple redundant emergency backup? My point was that if done right with two pipes you still have no noise (since all the flow during normal operation is going through the primary without any air) and all the emergency backup you need. If you want to break up the secondary pipe into two, three, four, or more pipes... go for it, but if done right from the start, you will only ever have water flowing through two of the pipes anyways, the primary and when it backs up enough, the secondary/backup. The secondary should be large enough to handle all of the water flow without any restrictions from the overflow should the primary be clogged. The third pipe serves no purpose other than as a backup to the backup... If done right, the probability that you will ever need that third pipe drops to 0;, so why bother?

I think the reason for the triple pipes comes from two design "flaws" that aren't really necessary in the first place. One is that this style that Bean came up with has a very shallow overflow area, which means a very limited range of 'self adjustment' with the primary. I have seen tanks where the overflow was simply just the one primary pipe with a valve control at the bottom. They used mesh on the intake to prevent clogs and cleaned it on a very regular basis to prevent major clogging, but it does work. The gate valve at the bottom is tuned to "back up" the water in the tank overflow up to about the half way point... as the valve clogs or purges, the level either goes up and down, the pressure balances out, and its no big deal. This of course, assumes you have an overflow box height of at least 18". If your overflow depth is shallow, the primary pipe has very little room for 'self adjustment', and this is why the secondary "durso" pipe is added. Trying to use a gate valve restricted standpipe in a shallow overflow is next to impossible, and self defeating in application. I prefer to have a coast to coast that drains into a taller height overflow box for this very reason. The gate valve restricted standpipe used as a primary needs a few inches at least for it to 'self-adjust'; lacking the height means it will either start sucking air in or backup and cause water to go into the next pipe that much easier. You will end up having to adjust the valve that much more frequently the shallower the overflow is... so if you are going to have a gate valve regulated no-air primary drain, do yourself a favor and apply it like it is supposed to be... in an overflow box that is at least 12" tall. This will do more to kill noise than any triple, quad, or higher number drainpipe method.

The shallow overflow box pretty much is the reason for the second pipe needing some sound silencing. Perhaps a better way to understand what I am getting at is that Im actually talking about a primary and secondary that would consist of the primary and third lines (skipping the middle durso-ish one) in the Beananimal system. The whole reason that Bean needs the second line set up to block noise and the third to back that one up is because his shallow overflow area doesn't allow for much 'self adjustment' with the primary, and he's pretty much betting on some regular use of the durso-ish pipe. With some extra height in the overflow though, this problem is eliminated as the primary can self adjust itself with even less noise than what Bean's system would cause because you will likely never have water and air in any one drain pipe at any time... so no trickle.

The second flaw (and Bean has admitted to this), is that he is just using too small of piping for the secondary and third pipes. If he just used one pipe large enough to handle the entire flow volume, the third pipe is useless (or skip the second and keep the third if you want to look at it like that). The reason he came up with the three pipe system is simply because he wanted to use more pipes of smaller diameter, and because the shallower overflow causing the more frequent use of the backup pipes that means more noise to deal with... and thus the need for a noise-handling backup (durso-ish) comes into play and then due to the startup problems with this, another backup is needed. The thing is, if the overflow was just taller and the primary given more height to "self-adjust", the probability of ever needing the other pipes goes down very significantly. Not even needing to rely on a drain pipe that might have air and water in it means no trickle, no air suction, no bubbles, and so 0 noise and a system that is even quieter than the Bean system.

 

[Hahnmeister]

On external vs. internal, I have a different viewpoint:

External is easier and safer.

- If an internal overflow box leaks, you can empty the entire tank contents into the sump. If an external overflow box leaks, it simply dumps what is in the overflow, but the tank will remain filled.

- I think its easier to find a place that is able to slice the top edge of a tank down a little than it is to drill holes. FWIW, if you are having a hard time finding someone to slice a panel down, you can simply remove the panel (cut the silicone), and replace that side with a shorter cut panel.

-Cutting the top edge of a tank panel down is less of a structutal comprimise than drilling holes (muliple holes) into the bottom or back panel of a tank. Drilling the main tank usually means extra consideration must be given to beef up that panel to make up for the added stress of having a hole in such a high-pressure area. A slot along the top of the tank is pretty much the lowest pressure and stress area you can have.

- Along the lines of the last point... drilling the holes with an internal setup either means your tank is going to have a beefed up panel (perhaps the whole bottom needs to be thicker, the tank heavier, etc), and the holes will need to observe some sort of minimal spacing requirement so that the water pressure and stress on the lower portions of the tank doesnt say... just cause one crack to form through three or four holes arranged into a "conveniently arranged" square or line.

Since an external overflow is often containing much less water pressure, lower height, can depend on the main tank for some extra support on at least one side, etc... the hole sizes, spacing, etc... can be less of a concern with respect to structural support of the drilled holes and panels. An entire tank of many hundred gallons may use overflow glass that is a fraction of what the main tank's glass would be, which also means much lower cost to get those holes drilled as well. Since a smaller box also means side panels lend that much extra support to the panels it meets with, the hole spacing and configuration is more relaxed as far as structural concerns.

-In case you ever want to change something about the overflow... make it deeper, larger drain pipes, etc... an external allows for this without tearing down the tank. Simply shut off the sump return pump and shave off the silicone from the outside of the tank. Removing/replacing an internal overflow box... you're talking about a total teardown.

-IME, externals offer better access. Internals tend to be inside the back edge of the tank, in corners where internal pumps may be as well, partly covered by parimeter or cross bracing, or in the middle where its just harder to get to them...not to mention harder to cover up from view in the tank. Externals are not "under" the lighting hood or in a corner with multiple other things... they are outside after all and alot easier to inspect, clean, etc.

 

[Russter]

Some good points, but not sure what you mean by noise. All the bean-style systems I have had have been completely 100% silent with no noise whatsoever and completely set and forget. I used 1.5" pipes and the overflow is only 4" deep. And while I can somewhat see your reluctance to have a the third pipe, I for one, like to have as many backups as possible in case of failure. It does not take much to add the third pipe and seeing as space is not an issue the peace of mind it gives is more than worth it.

 

[Hahnmeister]

If either system only ends up using the primary drain pipe, then they will both be silent. The shallower overflow will mean that the secondary standpipe will have a higher frequency of use, and when it is in use, it will make noise like a durso, as in trickle, flow, bubbles, etc... the noises a durso/stockman/etc. or any type of standpipe with both air and water flowing at the same time will have. The taller overflow will allow the primary standpipe (if you even use a standpipe for it) more height to self-adjust with respect to the adjustment valve vs. the head pressure in the overflow... so less likely use of any backup piping.

 

[ajnoplay]

Does anyone have any pictures of a glass tank with the external overflow I am in the process of building a 96x30x30 and would love to have more room in tank.

 

[Aquaph8]

[/IMG]

 

[Zombie]

What would happen if you use a T at the surface of the over flow box instead of an elbow with an air hole. Run the air intake pipe up to an elbow and through a wall. The intake noise will be behind or in the wall. would this make the display quieter?

I was going to use the two drain method in my corner overflows, but if it is going to still make a trickling sound down the second pipe what are the advantages? I thought the second pipe would be dry unless needed in an emergency.

 

[ajnoplay]

@ Aquaph nice tank. I might do a external on the 30 inch side of tank.

 

[Aquaph8]

Thanks, I love my external overflow and the bean animal drains are awesome.

 

[KSzegi]

Does anyone have any pictures of a glass tank with the external overflow I am in the process of building a 96x30x30 and would love to have more room in tank.