"Calfo" Overflow Design

[808-340]

Hi all...
I am in the process of setting up my 110gal and am interested in using a "calfo" design overflow. I know there's a thread regarding this and I've read through almost all of it.

My question:
How long should I make the overflow? I've done some preliminary designs and have made an overflow that is 16x4x5-inches. The reason for the width is that I wanted to use 90-deg elbows in the overflow. Placing it next to the tank, it looks small... Should I make the overflow longer? Any feedback or comments are appreciated! BTW, I'll have 2-1.5" bulkheads in the overflow and the tank is 48" wide.

Thanks!

[BeanAnimal]

The longer the better. The whole premise is to get the thinnest sheet of water possible.

[xtm]

Calfo overflows usually go coast to coast.. from one end to the other.

[808-340]

Thanks for the responses. Yes I know that the longer the better and that it is considered a "coast to coast" design, but does anyone know if there is a "ratio" of length of overflow to length of tank that is ideal or that is "not worth doing" because of the short length of the overflow?

[bernie lyons]

designed and owned a seven foot tank with a coast to coast overflow years ago .The only problem is that you MUST make sure that the tank is perfectly leveled side to side , otherwise only part of the overflow will work leaving the other side useless .
bernie lyons

[woz9683]

The "ideal" is as long as possible just like Bean said, the ratio for "ideal" tank length vs. overflow length would be 1:1

[tas5tas]

Here are some pictures of my overflow for reference.

[BeanAnimal]

Wow, that takes up a good bit of room! It looks very clean, but I am not sure I could live with the reduction in space.

Mine is as small as I could make it and still get the elbows on the bulkheads.

Next tank will have a full length overflow, but it will be on the outside.

[woz9683]

That's why i love my design Bean, no interference at all

[BeanAnimal]

I have been kicking around the idea of replacing the 75 AGA with a plywood tank... more closed loops and an external overflow. I just can't bring myself to take on the work!

[tas5tas]

It doesn't stick out that far anymore....before I started the cycle, I trimmed it and it only sticks out 1". It works beautifully though. Now if I could get my stupid coralife skimmer to work.

[mxett]

What is the advantage of having the overflow over such a large area?

[tas5tas]

The advantage is the skimming of the entire surface of the tank which in turn equates to higher efficiancy.

[808-340]

Again, thanks for the responses! I'm planning on running two 1.5" bulkheads and one or two 1" bulkheads slightly higher than the 1.5" bulkheads. How many are using elbows and how many are not? If elbows are not needed, I can make the overflow about 1" out from the tank wall.

[tas5tas]

There are no elbows inside of my overflow. To stop the flushing sound, I placed a T on the bulkhead outside of the tank instead of a 90 going to the sump and put a cap on the top of the T with a 1/4" hole drilled in the cap. My tank is so quiet you can't even tell it's in the room and I have a 40x an hour turnover rate.