Tank/c2c overflow design help

[Pprice01]

Hello all,

As I make my way through the various options and opinions to the coast to coast overflow, I have come across an option when working this out with my reef buddies here in Vegas that I would appreciate your feedback on.

When installing the weir, instead of building an overflow internally on the back wall of the tank that then flows through holes into the external overflow, would there be an issue with installing it as part of the side wall instead?

I understand that this would certainly limit my surface skimming, but it would allow me to have a deeper tank than standard as the plumbing and external box would not be in the back, but rather on one side.

I am wondering if I could get the tank manufacturer to actually make the wier out of the side wall by simply making the tank wall itself shorter by the appropriate level maybe 1/2" or 3/4"?

I am thinking that I would then have an external box added to this shorter side wall/weir so that I could run my bean animal drain system.

I would like to eliminate the internal box look as well as reduce costs, and if I shorten the overlow by moving it to the side of the tank maybe it would solve both issues.

I am also thinking that I could build cabinetry would hide the overflow box since the tank is going between two bookshelves - I should be able to disguise it.

Can anyone forsee any flow problems with this design? Any suggestions at all would be greatly appreciated.

If this doesn't make sense please tell me and I'll try to work up a sketch.

 

[shaggss]

It's called a "Peninsula". Should be no probs, lots have already done it. As you said though, the surface skimming will not be as good. A couple of well placed returns/PH will mitigate any worries........

Good luck

cheers :beer:

 

[Pprice01]

Thanks Shaggss.

Anyone ever utilize the side wall of the tank as a weir by cutting it shorter, or are people giving up real estate inside the tank to de an internal overflow box?

I would prefer to not lose the internal space, but sacrifices sometimes must be made.

As for flow, if I run the overflow from one side of the tank, what is the best way to make sure that the proper flow is achieved? Is it simply a circular motion around the tank via the return pump and maybe powerheads? I would like the tank to look as clean as possible so I'm curious to see what people have done.

I'm thinking a 60" or 72" tank at the longest.

Thanks Everyone!

 

[Pprice01]

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[shaggss]

You can also add another hole to the overflow/weir and have the return up through it. have it go along the back of the tank then you can add nozzles where ever you like.

 

[tkeracer619]

After seeing how a friends coast to coast worked I won't ever use one. Not worth it IME.

Why create an overflow that doesn't surface skim? What is the benefit of a coast to coast? I haven't seen one and they seem to reduce the structural strength of the tank itself.

 

[Pprice01]

I don't understand tkeracer619 - why wouldn't this overflow skim? If I have a 24" deep tank the weir would be 24" of skimming. Is it absolutely necessary to skim over the entire length of the tank? the tank will most likely only be 60" L, so the 24" is almost 1/2 of that length, and well more than any standard overflow box would provide.

The main use of the overflow box would be to allow me to incorporate Bean's silent overflow without giving up real estate in the tank, the skimming is secondary.

I could just as easily have the glass shop put an inner wall 4" from one side with three holes out the side of the tank for the overflow, but again, I am trying no to lose too much internal space.

As far as the flow goes, I'm still not sure about that. Should I use the return pump on the same side as the overflow, but lower down the tank with Powerheads on the opposite sides at the top to make sort of a vertically circular? flow pattern with the top returns pushing back toward the overflow? (not sure that even made sense to me, so I'll sketch something and post it later)

Thanks everyone.

 

[tkeracer619]

A properly designed overflow will suck anything that gets close into the overflow.

If you keep the water return the same as you lengthen the overflow the water goes over the overflow easier. The water doesn't build up height and will have less potential energy.

Think about a stream or creek. A slow flowing stream will have a lot of debris caught on sticks and stuff particularly on the sides but a fast flowing stream does not.

You want that falling water to rush into the overflow, it will suck the surface junk into the overflow so it can be processed by your skimmer. A coast to coast overflow has less potential energy and slower flow into the overflow box. It will pull less waste into it and you end up getting a film on the top surface.

As you said though, the surface skimming will not be as good. A couple of well placed returns/PH will mitigate any worries........

You can use pumps and returns to solve the problem but I would rather use and aim them for corals and detritus removal.

 

[Pprice01]

Maybe I misread Bean's thread in that you only wanted a very thin sheet of water going over the weir - to which I should be able to dial back my return pump to accomplish the goal.

What are people to then who don't want to have the entire back of their tank used for an overflow? What options are there for a peninsula-style setup that would be better than the c2c on the side with powerheads or other returns moving the water around?

 

[Pprice01]

Here's the dilemma - would it be better to simply add a shorter wall to one end of tank (there's my weir) and have the bean drain system come in through holes drilled in the bottom of the tank, instead of adding an external overflow box/weir and have the holes/drains come out the side?

Pros:

1. Simple
2. Inexpensive
3. Utilize a larger tank (a 5' tank is planned with an external box, however, with this design I might be able to squeeze a 6' tank into the same footprint, but with the wall I might lose maybe 6" - this would give me a 5' 6" internal dimension - so 6" longer tank in the end.)

Cons:

1. Loss of tank real estate
2. Deep overflow? (not sure this is a con)
3. Bottom holes? Any different that holes on the side in an overflow box for siphon effects? The overflow wall should effectively be the break point for any back siphon I think - am I right in this thought?

Or would it better to have an interna overflow box built on the end (with the bean system going through holes built into the side) to give me room underneath for powerheads, etc.?

 

[Mouse]

What are the dimensions of the tank you have? Sorry if I missed it up there somewhere but it is an important piece of the puzzle. Also, what kind of flow will you have in the tank? SPS, LPS, Softies, fish only? There are alot of factors to conceder when setting things up.
Why the Bean overflow? Im not saying its bad or anything like that, just curious why your set on it so.

 

[Pprice01]

Mouse,

I'm thinking of a 72" x24" x 20" mixed reef - mostly LPS, softies, and fish with some SPS.

I will have the tank in my home office so I need it to be as quiet as possible. Also, it's going upstairs on carpet, so failsafe is also important.

Paul

 

[jitasb]

Hello.

I know this is an old thread, but it came up my search as this setup is what I am considering as well.

Just wondered which of the options you went with in the end ?
- shorter end tank wall with external box ?
- shorter tank wall inside the main tank to act was weir and then holes in base for pipes

You listed the pros and cons which was useful as I came up with the same. Also I thought of some other considerations as follows:

External Box: if it runs entire side wall. does it need to be strengthened and/or supported underneath? As it is outside the main tank and any failure would be leaking directly onto the floor.

Deep overflow inside main tank with holes in base : This in effect is same as any weir inside the tank, but larger as it goes all the way across. Because of the higher volume : will this cause detrius to settle at bottom and hence need more cleaning ?
Also on this model : you couldn't put a powerhead (like vortech) on this wall as it would be under water ?

Thanks