Underflow/Overflow Design

[JardiniBoy]

I'm think of having an under/overflow for my new tank. The purpose of the underflow is to suck debris from the bottom of the tank. The overflow acts as a surface skimmer and prevents your house flooding in the case of a power outage / pump failure.

Here's a basic pic:

I was wondering how I should calculate the sizes of the gaps at the bottom and top of the underflow (A and B in the diagram). The idea is to get some water going over the overflow and some through the underflow. I'll be using 2xViaAqua 2600s (2600 liters/hour) and I would like the overflow/underflow to run the width of the tank - 60cm.

Any ideas?

I would really appreciate any feedback on this as I wanna get it properly designed before making it, or it's gonna be a huge ball ache to try fix after the fact.

Thanks in advance!

JB

 

[ChrisGray]

looks good to me, the design seems like it should work well for you

 

[JardiniBoy]

looks good to me, the design seems like it should work well for you

Okay ... but any ideas on the calculations for the sizes of those gaps as mentioned above?

 

[rook45]

i don't have any calaulations but would love to see pics when it's perfected and running

 

[hanks]

Unless I miss understand your drawing, Many of the reef ready tanks you can purchase have a similar setup. Could you take a look at one in your LFS and get an idea from that.

 

[RowingMunkeyCU]

Unless I miss understand your drawing, Many of the reef ready tanks you can purchase have a similar setup. Could you take a look at one in your LFS and get an idea from that.

nah, they really just have the top overflow, the closest you can get is one of these overflows made by all-glass:

the problem is (from what i can tell), that there is nothing actually pulling the water in at the bottom and middle intakes, so the water continues to flow over the top, like a regular overflow.

 

[RowingMunkeyCU]

taking a look at your design, you may have a problem trying to get water suction from the bottom intake. you would need to have some sortof suction, whether by a syphon or by a pump. if you want to take the syphon route, the outlet of the syphon needs to be below the intake, which would be quite difficult to accomplish in-tank. something like an external weir would possibly be more effective, although you would have to be careful if the syphon stopped...

 

[ROSS]

 

[JardiniBoy]

Thanks for all the replies!

I'm not sure that you all understand the design. The suction through the bottom is created by gravity. This arises from the height difference between the top of the overflow (top of D in my diagram) and the top of the glass wall of the overflow chamber (C in my diagram).

I already have some equations and I've calculated it, but I wanted to cross reference with you guys.

The key elements of the equation are the difference in height of the two pieces of glass mentioned above, and the area of the underflow gap (B in my diagram)

Any ideas ... ? (physicists please chip in )

JB

 

[JardiniBoy]

bump