Calfo Style Overflow boxes

that's it, hampton, here's the link:

http://reefcentral.com/forums/showthread.php?s=&threadid=730564

it's been a while since i've been through the entire thread, but about page three is where you get to the CAD designs. the first 7 pages or so pertain to his pre-construction design work, that's what i'd recommend reading for overflow ideas. the entire thread is very worthwhile reading, sanjay teaches industrial design at penn state and is an experienced reefer. he discusses every element of his system in great detail prior to the build, and it's remarkable to see the finished product actually meet his design.
 
Can anyone tell me the benefit of having a calfo overflow compared to just a ninety coming out of your bulkhead to drain the water? Is it just because it hides the pipe and looks better or is it something else? I am building a 40 breeder and just curious. thanks
 
I have a question, what do you guys think instead of having the overflow box in the back, its placed on one of the sides? That way theres more room in the back for aquascaping? I've been reading this thread for a while and i was gonna do one on my 75 gallon I was gonna put it on the back but then i thought about putting on da side what do you guys think???
 
<a href=showthread.php?s=&postid=8934376#post8934376 target=_blank>Originally posted</a> by cbcostanza
Can anyone tell me the benefit of having a calfo overflow compared to just a ninety coming out of your bulkhead to drain the water? Is it just because it hides the pipe and looks better or is it something else? I am building a 40 breeder and just curious. thanks
Click to expand...

Not an expert but I think it has to do with the increased area of surface disturbance.
 
IT is all about surface skimming. The protiens tend to collect at the thin (molecular) air/water interface. We want to sweep as much of that off of the surface as quick as possible.

Think of an oilslick. Oil floats on water. Given the same flow rate a LONGER overflow with a THINNER sheet of water will move more oil over the "dam" than a narrow dam with DEEPER flow.

In other words every time you DOUBLE the width if the weir, you half the thickness of the water going over it and DOUBLE the speed at wich the "oilslick" disapears over the falls.

In our tanks, the faster we can get fresh water to the surface, the faster some of the protiens in the water will be attracted to the surface tension. We want to move them over the falls as fast as possibe to make room for new bonds.

The idea is to get the richest protien water to the sump for export (skimmer, fuge, rdsb, whatever) instead of leaving it in the tank to grow algea.

Bean
 
I guess I should have also mentioned that in your case a single "90" will not remove enough of the surface skim fast enough to prevent surface scum from forming on the water surface.
 
I have some pics of my set up previously seen during construction on page two of this thread.





10083IMG_0363a.jpg




10083IMG_0364a.jpg


10083IMG_0365a.jpg


10083IMG_0360a.jpg
 
So, I'm drilling my 58g this weekend and push about 300gph through return. So i decided on 2-1" bulkheads with external stockmans then flexspa to sump.

My question is, how do i determine what the least width and height is i could use for the weir? not going to use elbows as 300gph shouldn't ever make the drains completely submerged(correct?)
 
I would still make the width and height enough to account for elbows in place, just in case you may need them. If you don't, and end up having a major slurping sound, you'll be upset that the weir is already in place and you now can't put in elbows.

The difference in width and height without using them is not all that significant, although I don't know if they will be in a 58gal. What are the dimensions of your tank?
 
Another thing to consider...Make sure that you can easily clean itand retrieve things from it. I made mine about the width of my hand. I didn't consider that when you make a fist (like when grabbing something or trying to clean) your fist is a little wider. I can still do it, but its tight. I wish I had another 1/4 to 1/2 inch.
 
You want it deep enough to handle a down turned street elbow with maybe 1/4" to 1/2" of clearance under it. In other words just deep enough to do the job. Mine is a bit too narrow but it worked out very well. I had to trim the male side of the street elbows down to get them in.
 
BeanAnimal......I have a question, if the flow in my 58g is so that the surface looks like a breaker zone, would this style overflow work?
 
You still want to clear what is there as fast as possible.

As far as "constant" the return pump dictates that. So over any reasonable time T, the flow rate over the falls will be the same as that being pushed into the tank and forming waves.
 
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