depth of overflow teeth?


New member
How deep below water line should you make overflow teeth? I am making a small surface skimmer/overflow to go inside my 10 gallon I am setting up for a mantis. Stumped at the teeth. How deep?

I just got on here looking for the same exact info. I usually make mine 3/4" deep. There is a link to a cool calculator on the home page that will tell you the linear amount of overflow needed. Im assuming that they are using a 1/4" wide cutout but Im not exactly sure what depth.

ooo sounds like math lol. THe calculator says I need 3 inches. Would that be 3 square inches? Basicly this isn't draining to a bulkhead or anything. It is for my AC50. Water overflows in the overflow area then gets sucked up by AC50. So I get surface skimming and gass exchange.

I was thinking like a total of 6 teeth. 1/4 inch wide and 1/2 inch deep. That would be 1/2 from the top of the overflow. So the water level would be a bit lower. Maybe I need to go 3/4"?
I just made a surface skimmer for my overflow out of a Lees spcimen container .
I cut the teeth 1/4" wide and 1 1/4" deep. The skimmer mounts to the overflow with a nylon screw and wingnut. The mount on the overflow is slotted so I can adjust the depth ofthe skimmer box in the water.
The linear overflow calculator has nothing to do with flow. It is designed to determine the minimum amount of linear overflow length to achieve good surface skimming. Teeth reduce the amount of "linear overflow" at least the sum of the width all the solid teeth in your overflow. In other words if you have an overflow that has a perimiter of 10 inches, and you cut 1/4" teeth 1/4" apart, then your total "linear overflow" is 5 inches. Or look at it this way. If the water over a FLAT 10" overflow was 1/4" deep, then the overlow with 1/4" teeth 1/4" apart would have a flow depth of 1/2".

In other words, if you can get away without using teeth, then by all means do so.

Hope this makes sense.
yeah but I thought teeth were good to help break up the water and provide better gas exchange. I am fine going flat, I have flat on the cassette tape over flow on my 24 NC. Just trying to get it set up right lol. Flat is easier even.
yeah the overflow is mainly to surface skim and provide some agitation to the water. I guess I will just do a few on each side 1/4 wide maybe 3/4 deep. SHould be enough.