Durso tuning help needed

[Thunder_reef]

So I’m trying to set up and tune a Durso, I have read Durso web page many times but I’m still confused about the vent hole at the top. The drain doesn’t seem to be as fast as I thought it would be. Would a larger or smaller vent hole allow the drain to flow faster??

Thanks in advance

 

[Boehmtown]

Your draining speed is linked to your return pump, the vent hole is to keep it from gurgling , the slower your flow , the larger the vent

 

[Thunder_reef]

That’s what the Durso site says, but l don’t follow that statement. Let me rephrase my question. If the vent hole is too small, what will happen? Slower drain or faster drain or no effect at all? If the hole is too large, same question.

 

[Boehmtown]

Just noise and gurgling will be effected. Drain speed is not linked at all

 

[SteveMM62Reef]

You can increase the flow by using thinwall PVC, going up one pipe size from your Bulkhead Fitting and using a Reducing Coupling rather than a Bushing. Also the reducing coupling makes less noise. Another thing you can do is to put a “Y” on filter sock end, a riser pipe, with a cap and drill a small hole in the cap, to mitigate the noise on that end.