DIY All in One Overflow size?

[ahud]

How do I calculate the length and depth of my overflow on a 10g DIY AIO? I am not going to run any teeth, just a notch cut in the top left corner of the false wall. The false wall will go on the side of the tank "Penisula style".

Would 3" long and 1/2" deep be sufficient?

I plan on running 250-300gph through the sump section.

 

[ahud]

Also only planning on running one baffle. The area is so small I am not going to run a skimmer and a fuge seems a waste.

Here is a basic outline:

 

[mcgyvr]

Plenty of calculators out there..
http://irrigation.wsu.edu/Content/Calculators/Water-Measurements/Rectangular-Contracted-Weir.php


http://www.codecogs.com/library/engineering/fluid_mechanics/weirs/discharge.php

 

[ahud]

Thank you very much. Exactly what I needed.

Last thing, any reason to oversize the overflow? Once I cut the acrylic, its done unless I can rig up an adjustable weir.

If the overflow is too large, the distance between the water level in the display and the water level in the internal sump will increase causing noise from water falling correct?

Edited to add:

As far as depth, I am concerned about critters getting in and surface skimming. Does 1/2" sound right for that? If I make my overflow 5" wide by 1/2" deep then my weir can handle 300gph.

 

[mcgyvr]

The math tells us that if Q stays the same and you increase "L" then you decrease "H".. plain and simple..

Where:

Q = Flow Rate.

L = Bottom width of the weir

H = Height of the upstream water above the weir crest


Reality has shown that an increase in L improves surface skimming provided Q is sufficient.. So for the most part a "coast to coast" weir is better than a corner overflow box..
The coast to coast tank will have less "surface protein" issues (the oil slick present on the top of the water)

If you can reduce "H" to the point where critters cannot fit through that then you don't have that problem.. So thats another reason that increasing L and decreasing H may be beneficial..

 

[ahud]

Can't get any simpler than that. Thank you, sir.

Last question if you care to comment. I am just doing one baffle because I am not running a skimmer. I don't think microbubbles will be a concern. I'm mainly using the baffle to force water down through the carbon/GFO.

Do you see any major flaws in that logic? Guessing you are in the wastewater/treatment business?

 

[mcgyvr]

Not at all in the wastewater/treatment business.. That sounds like a "crappy" job

The only comment I would have about your question is that I always try to remind people that GFO is intended for those with a real phosphate problem that they can't solve via other means.. I will never recommend people just use it without a darn good reason to do so as it can cause more harm then it helps.. Its quite powerful and can strip a tank of much needed phosphate..

Not to mention you are talking a 10G tank here... Personally on such a small tank water changes alone are all that are needed to maintain proper water chemistry and nothing that I can think of will do it better than water changes will..

 

[ahud]

Haha, "crappy" is one word for it.

This is my first nano. I tried to copy successful tanks that have been running for multiple years. I found several of them used GFO, but some were SPS tanks. I can leave the GFO out until needed (if ever), I'll have a place for it in the media basket should I need it.

Thanks again for all the help, I'm going to go cut my pieces and put this tank together.