external oveflows

[pdfrogman]

posted this Large tank section but got no response so I figured this would be a better place to ask


hello been along time since I've posted here currently I have a 180 mixed reef. glass tank with full glass canopy.
I'm planning on a new tank for a couple of reasons
1. this tank is very difficult to work on with full glass canopy constantly keeping top clean so the light gets through.
2. I want to make this system a little more energy efficient and easier to work on

so far I'm planning on a steel stand with a removable wood skin
the tank will be acrylic 1" thick 72L X 36W X 24T
I am building the tank and originally was going with 2 corner boxes but toying with the idea of external overflow boxes ( hence the thread title) to make it easier to maintain
so if it's not too much trouble lets see some overflow boxes!
I need some ideas!

rather than router out slots in the back wall was thinking of a slot where I can slide in egg create or another type of screen so I can keep it clean
suggestions?
Thanks!


PS it's been so long since I posted I had to re register

 

[BeanAnimal]

I would simply make the back wall of the tank shorter and attach an external overflow box to it. The box will stiffen the back wall. You can add a vertical brace or two if needed.

Superb surface skimming and easy to maintain.

 

[pdfrogman]

how would you keep live stock out of the overflow?

 

[BeanAnimal]

Let the snails come and go as the please

With an overflow that wide, the water going over the weir is very thin. Very few fish will take the trip. Sometimes shrimp make their way to the sump... But they go through eggcrate anyway.

 

[pdfrogman]

that makes sense I have purple puesdo that concerns me and I want another mystery wrasse.

how big would you make the slot?
I was planing to make 2 seperate boxes spanning the length of the tank +/- a couple of inches at least 12-14 deep

 

[pdfrogman]

no other input????

 

[SkyPapa]

Not to put words in Bean's mouth, but when I read his response I took it to mean no slot, but the ENTIRE back wall with the overflow box to equal the length of the tank.

 

[pdfrogman]

I understood. the plans for the tank will have a 6" lip around the top with a 6" center brace
I guess I could extend the top to cover the overflow box too and router in removable covers

I saw they overflows in Sanjays 500 which gave me the idea of the egg create

 

[SkyPapa]

Sorry then, when you asked "how big would you make the slot?",
I guess you meant depth.
And I don't have an answer, should have just left the keyboard alone.
Bean is the man for overflows.

 

[Horace]

external overflows scare me . I love the idea, but after reading about some folks doing it and having the back of thier tank blow out, im not sure I would risk it. On a smaller tank it might not be too bad, but on a larger tank, (6' or longer) im not so sure I would give it a go. I would need to see one designed and in operation for a while to chance it...

 

[pdfrogman]

<a href=showthread.php?s=&postid=12597210#post12597210 target=_blank>Originally posted</a> by Horace
external overflows scare me . I love the idea, but after reading about some folks doing it and having the back of thier tank blow out, im not sure I would risk it. On a smaller tank it might not be too bad, but on a larger tank, (6' or longer) im not so sure I would give it a go. I would need to see one designed and in operation for a while to chance it...

]
maybe corner boxes might be the way to go

 

[JCTewks]

corner boxes have notoriously poor surface skimming capability's.
You could always do an internal coast to coast with 3 1.5" bulkheads with external plumbing for your overflow. Then, you'd have the full length of the back of the tank for surface skimming.

 

[Horace]

<a href=showthread.php?s=&postid=12597591#post12597591 target=_blank>Originally posted</a> by JCTewks
corner boxes have notoriously poor surface skimming capability's.
You could always do an internal coast to coast with 3 1.5" bulkheads with external plumbing for your overflow. Then, you'd have the full length of the back of the tank for surface skimming.

After seing Bean's (or what is Hahn?) design for three drains, which sounds similar to what your saying JCT, I think I would feel safer going with the internal coast to coast. It wouldnt need to be very large (tall/wide).

 

[Acrylics]

Given that you are referring to an acrylic tank for this overflow and 1" at that, if done right - you will have no issues at all with strength when it comes to the external. You will be able to literally carry the tank by the overflow alone, again if done right.
Make two slots though, one on either side of your crossbrace. If you make the slot going the entire length, the crossbrace won't do anything - you want it to connect to the back of the tank. If you don't plan to use teeth in it - 3/4-1" height on it would be sufficient to allow several thousand GPH with an air gap between the surface an underside of the the bracing. If you did want to use teeth, the slot height will be determined by the GPH you are wanting to flow through the overflow.

I'll see if I can't find a pic or two for ya later today.

HTH,
James

 

[Horace]

I was thinking about a glass tank rather than acrlyic. What happend with the other guy's tank that broke was where the center brace was attached to the back, that part snapped right off. After that, the back bowed/cracked/blew out.

 

[pdfrogman]

<a href=showthread.php?s=&postid=12598189#post12598189 target=_blank>Originally posted</a> by Acrylics
Given that you are referring to an acrylic tank for this overflow and 1" at that, if done right - you will have no issues at all with strength when it comes to the external. You will be able to literally carry the tank by the overflow alone, again if done right.
Make two slots though, one on either side of your crossbrace. If you make the slot going the entire length, the crossbrace won't do anything - you want it to connect to the back of the tank. If you don't plan to use teeth in it - 3/4-1" height on it would be sufficient to allow several thousand GPH with an air gap between the surface an underside of the the bracing. If you did want to use teeth, the slot height will be determined by the GPH you are wanting to flow through the overflow.

I'll see if I can't find a pic or two for ya later today.

HTH,
James

Thanks I was hoping you would chime in
I do like the idea of not having teeth to clean (one of my reasons for this new tank project)I cant get to the teeth in my corner box now on my tank.

most of my fish now with the exception of 2 clowns and puesdo are at least 4"+
worried if I add any small fish them gettting trapped.


I plan on running dual drains an smaller drain to gravity feed my skimmer and most likey going to run a dart as a return
I have the large tunze streams to move water internally

Thanks! ror the input guys!

 

[wmilas]

On an acrylic tank, external overflow boxes actually make the tank back stronger, not weaker, as mentioned above. I have dual 36x8x16 external overflows on my 120x36x30. The back is one solid piece of acrylic, just like the front. Imagine a box with no overflows and with the bracing. Now attached the overflow boxes to the back of the tank and route in the overflow teeth. The eurobracing can completely cover the overflow box if you want (no need) or route in an opening so you can have access. Better yet bevel the opening so you can put a lid on the overflows (I did

There is no additional stress this way. In fact the back is even stiffer.

 

[pdfrogman]

<a href=showthread.php?s=&postid=12598788#post12598788 target=_blank>Originally posted</a> by wmilas
On an acrylic tank, external overflow boxes actually make the tank back stronger, not weaker, as mentioned above. I have dual 36x8x16 external overflows on my 120x36x30. The back is one solid piece of acrylic, just like the front. Imagine a box with no overflows and with the bracing. Now attached the overflow boxes to the back of the tank and route in the overflow teeth. The eurobracing can completely cover the overflow box if you want (no need) or route in an opening so you can have access. Better yet bevel the opening so you can put a lid on the overflows (I did

There is no additional stress this way. In fact the back is even stiffer.

Thanks I'm leaning towards no teeth just one thing lest to clean.
I'll have plenty of 1" scrap to make the overflow boxes
can I bother you for a pic?

Thanks!
FRANK

 

[wmilas]

Well the tank is wrapped in tarp right now as the fishroom is being epoxied. As soon as I unwrap it I'll take a few shots.

 

[pdfrogman]

<a href=showthread.php?s=&postid=12601176#post12601176 target=_blank>Originally posted</a> by wmilas
Well the tank is wrapped in tarp right now as the fishroom is being epoxied. As soon as I unwrap it I'll take a few shots.

thanks!