Overflow Standpipe Question

[JeffBowlin]

I recieved what I think is a "durso" style overflow standpipe with my new 150gallon rimless. It's 1-1/2" pvc, with a 1/2" hole in the top. Pictures I find on the internet however often show an air line, sometimes a valved air line, coming from the top of the standpipe.

I'm just wondering what purpose the air line and/or valve serve, and if I'll need or want one?

I'm also wondering if some sort of screen is required or recommended?

Here are some pics of what was provided:

 

[Reefmedic79]

You are correct, that is a durso. The hole you have pictured is to help prevent "flushing" of the overflow, in turn making them quieter.

The hole there appears to be a bit on the large side though. Placing some airline in with a valve as you mentioned will allow you to fine tune the overflow until it's at its quietest.

Sent from my future self.

 

[JeffBowlin]

Ah ha. Thanks. Once water is flowing, and depending on the noise, perhaps I can tap the hole and use a small MPT/barb fitting with some line and a valve. I suppose flow and water level at the stand pipe are variables in the noise equation.

Thanks again RM

 

[marietrg]

I have a couple Durso stand pipes. What I did was make a number of different caps each with a different hole size. I started at the smallest and kept working my way up until I found the optimal hole size. When I reached that point the flow improved and the flushing sound stopped. How that helps

 

[JeffBowlin]

It does, thanks.

I found some other threads that mentioned using a piece of tubing on the inside as well, extending down past the water line, so the air was introduced at a point that further reduced the gurgling.

Excited to get some water moving. Soon hopefully.