Two bean overflow boxes

[foxt]

I am planning a future tank build, and am trying to work out the overflow design. The tank will be 72"L x 30"W x 25"H. I would like a coast-to-coast external overflow. One of the tank builders I am working with will not build an external box longer than 24" long - he's concerned about the weight of a longer box.

So, I have three choices:
- choose a different builder
- live with the 24" box (which will have about a 14" effective weir length, based on his toothed design)
- put in two boxes

Has anyone run two external overflows with the bean drain design? I expect that for two boxes, I run two full sets of plumbing. I have a basement sump planned, and am targeting about 2400gph flow through the tank (Triton method, 10x flow). If I run two sets of drains, how do I size those?

With about 12' of head, I can get well over my target 2400gph through a 1" full siphon. If I run two overflow boxes, do I run two 1" full siphons to the sump? Is there some way to integrate the two boxes at the back of the tank and then run only one set of drain lines to the sump - such as run one 1-1/2 pipe between the boxes, and then run the bean plumbing from only one box down to the sump?

This all sounds more complicated than a single box, but I am not convinced that 14" effective weir is the best solution for 2400gph on a 240g tank - thoughts on that?

Tom

 

[jsker]

Bump, let see if you can get an answer today.

 

[beadlocked450r]

Yes i run 2 external overflow boxes. I will post some pics later, and i also have a basement sump

 

[richnbowl]

Can't wait to see the pics

 

[beadlocked450r]

I dont have a coast to coast but i do have the 2 external boxes. I have 1" running full syphon with a gate valve on each side and each side has an 1.5 emergency drain. I left the primary drains go straight down and tied the 2 backups together.

 

[beadlocked450r]

Ok so in this picture you can see the 2 1" drains and the backup drain. And you can also see the return back to the tank with the check valve.(check valve is only to keep pump from running backwards if i have a power serge) had it happen!

 

[beadlocked450r]

Here is a big picture of my basement mess!

 

[beadlocked450r]

 

[jsker]

You could use the ghost overflows here, this just another idea.

 

[foxt]

Bead - thank you for the pictures. What size tank is that (l x w x h)? Do you recall what the combined weir length is for your two boxes? I am wondering about the flow rate in each box - do they flow the same amount? Since you have two full siphons (one in each box), when the pumps first come on, how does the system behave?

jsker - I have ruled out the ghost style overflow. For me, it is an issue of the presence of the coast-coast internal box, and the hard horizontal line it seems to create across the back of the tank. I would probably not notice after a while, but since I am building custom, I figured I would just eliminate this as a variable.

 

[beadlocked450r]

84x30x30, yes both 1" are valved and from what i can tell flow the same. I tryed to make them the same length. When the pump turns on i get maybe 30sec of gurgles and surges and then its completly silent! I am running a reeflo barracuda hybrid with the big impeller, only thing on that pump is 2 small reactors, rest goes upto the tank, i would say atleast 4500-5000gph with the gate valves closed partly and could still flow more!

 

[beadlocked450r]

Oh yea and when i shut the pump off i get the same gurgles,like when a bath tub drains then its gone

 

[beadlocked450r]

I will measure the weir when i get home tonight, and my tank is 325g

 

[foxt]

Thanks. Although you don't have a bean system (no third channel), it is helpful to know that you do have two independent full siphons that start and run ok.

 

[beadlocked450r]

Yea sorry its kinda modified bean/herbie, and yes it does work without any issues! I have twsted it several times to make sure i wont ever have an overflow issue

 

[chiclids 1015]

I dont have a coast to coast but i do have the 2 external boxes. I have 1" running full syphon with a gate valve on each side and each side has an 1.5 emergency drain. I left the primary drains go straight down and tied the 2 backups together.

were are the 2 returns, im going to install 2 overflows in my 300