# A new 250 gal tank with sump and beananimal's overflow



## bakl (Nov 29, 2013)

I'm planning a new 250 gal tank to host a mix of tropheus and other tanganyikans.

I need your advice about sizing the sump filter, return pump and pipes. That's what I was thinking of:
- 50 gal sump,
- beananimal's overflow system with 1,25" pipes and fittings, 
- two Sicce Syncra Silent 4.0 return pumps with max flow of 900 gph each,
- overflow length about two feet.

Another thing: I'd like the overflow to also take some waste water from the bottom of the tank. If I add an _external filter style_ intake pipe just below full siphon opening, would that work?
I would attach a drawing, but unfortunately I'm not allowed to add attachments here.

So, what do you think?

Regards,
Bogdan


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## oyster dog (Jul 2, 2013)

bakl said:


> Another thing: I'd like the overflow to also take some waste water from the bottom of the tank. If I add an _external filter style_ intake pipe just below full siphon opening, would that work?


It would work, but probably not very well. I suspect it would not draw enough flow to make much of a difference. Besides, if you have good circulation in the tank there is no advantage in drawing water from the bottom of the tank.


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## bakl (Nov 29, 2013)

Thanks. I also figured out that once the return pump is shut down, the water from the display tank would drop to the overflow bottom. So much for this idea.

Anyway, still accepting suggestions about sizing the pipes and pumps.

Bogdan


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## chiroken (Sep 25, 2007)

Good questions, I will have similar ones so following this thread! Best article I've found on the method so far is here: http://www.glassreef.com/basics_overflow.php


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## bakl (Nov 29, 2013)

I've made a prototype of the system, it works pretty well: 





The downpipes become silent some 10 seconds after start.
Some splashing noise comes from the return pipes that should be submerged.
No bottom intake here anyway.

Another thing is the noise from the overflow itself - water flowing over the barrier. Any suggestions on how to deal with that?


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## SupeDM (Jan 26, 2009)

From my understanding there shouldn't be water flowing over the barrier but rather through the barrier via slots cut into top of it. Water in overflow should be at same level as tank water.


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## atreis (Jan 15, 2013)

This is a weir-type overflow (as opposed to the slotted sort).

Possible solutions:
1. Raise the water level inside the overflow box so that the water flowing over doesn't fall as far. (Yeah, I know, that means modifying your standpipes... A royal pain. Nonetheless, there you go.  )
2. Decrease the rate of flow through your sump/filter (which will decrease the amount of water going over the weir and possibly allow the water to "stick" (surface tension) to the side of the overflow box without breaking away and splashing.
3. Give the water a sloped surface to "stick" to via surface tension so that it doesn't splash down - getting this to work is tricky and you have little space for it... (You can play with the effect of this by finding the spot with the largest stream of water and sticking your finger in at an angle so that the water follows your finger - to see the effect it can have.)

If you cut slots, that would accomplish the same thing as #1 (by lowering the water in the tank some) but can add turbulence to the flow into the overflow box that could end up making it noisier (or not... lots of variables here). If you add slots on top of your current weir that will almost certainly make it noisier by raising the water level slightly in the DT and adding turbulence.

What you're really after in order to make it quiet is perfect laminar flow along a surface...

BTW - the BeanAnimal overflow is a really good design.


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## atreis (Jan 15, 2013)

Forgot to mention #2 above would require throttling back (via a valve, or smaller diameter pipe - in the photo, the middle pipe) your siphon accordingly...


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## lilscoots (Mar 13, 2012)

Best advice for a bean-animal type overflow is to put gate valves on the siphons, they allow you to fine tune exactly how high the water is in your overflow box. My 180 and my 125 both use this system and It is very quiet, it just takes a few days of fine tuning to get it quiet. I do have slotted overflows in the tank, but my sump baffles are not slotted, as long as the water is close to the same level on either side of the weir it should be quiet.


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