Target water height above the overflow weir?

[foxt]

I've read everything I can find on overflow design relative to toothless vs. toothed, etc etc. The consensus seems to be that toothless is better, and the design objective is to achieve as thin a cross section of flow as possible over the weir.

That said, I don't think anyone has set a target for this - just what is the ideal height for the water level over the weir? It has to be thin enough so as to skim the surface effectively, but presumably there is a min depth that we should tr to achieve. is that 1/4"? 1/2"? What does experience tell us?

 

[twilliard]

Fish won't go over that?
I have never heard of this design

 

[foxt]

Fish won't go over that?
I have never heard of this design

The debate usually is framed as part of a discussion about the coast to coast overflow design. In lieu of teeth, other steps can be taken to keep fish and other animals out of the overflow (gutter guard, a strategically placed cover, etc).

 

[Zenlikeyoda]

Is your goal for as silent as possible overflow, skimming of the top, etc? I have an external Bean Animal with teeth and the near silent I can achieve 75% of the time (such a finicky thing... or its just me lol), I have scoped out a (live) Peppermint shrimp that zipped into the overflow but fortunately no fish has attempted it. No real debris of film on top since I have my return bulkheads pointed a little more up to cause some agitation of the surface.

 

[foxt]

Is your goal for as silent as possible overflow, skimming of the top, etc? I have an external Bean Animal with teeth and the near silent I can achieve 75% of the time (such a finicky thing... or its just me lol), I have scoped out a (live) Peppermint shrimp that zipped into the overflow but fortunately no fish has attempted it. No real debris of film on top since I have my return bulkheads pointed a little more up to cause some agitation of the surface.

My goal is effective surface skimming ...

 

[foxt]

Did you consider having the tank built with an integrated overflow vs. using the ghost overflow? I had miracles and c2c both quote the build including their overflw designs, and they weren't that much different than the cost of adding a ghost.

 

[Zenlikeyoda]

Did you consider having the tank built with an integrated overflow vs. using the ghost overflow? I had miracles and c2c both quote the build including their overflw designs, and they weren't that much different than the cost of adding a ghost.

that is something to consider for my next tank!

 

[KingBlingTX]

The height of the water will be dictated by the length of the weir and the desired flow rate. If you want to achieve a certain turn-over (e.g. 5x tank volume), the height is fixed based on this rate and the length of the overflow. To minimize this height, you increase length to coast-to-coast style overflow and reduce flow rate to the minimal amount required for your tank.