Durso Standpipe Airhole

[SupaJSK]

How big is your airhole in your durso standpipe?

[phonnold]

1/8"

Could not believe how much less noisey the overflow is with this installed.

Philip

[ReefVan]

:D Here's an interesting take on the Durso or Stockman airhole in the cap.

Take a blank pvc cap for the top of your Durso or Stockman, cut a 1/4" to 1/2" long slot in the side of the cap at approx midway up the cap height. A hacksaw would give a nice fine slot.

Install the cap and mark where the slot falls on the Durso or Stockman underneath.

Drill a 1/8" or 5/32" hole in the vertical stand pipe where you made the mark at the slot height.

Install the cap and twist it as required to adjust your airflow. The slot will overlap the hole underneath and allow for an adjustment as you turn it. ;)

Van :cool:

[pr0nd3xtr]

Same as phonnold, about 1/8". Its a lot bigger than I thought, but it depends on how much flow you need through it. If I crank my return pump up all the way I have to restrict the air flow a bit. I think that was most of the fun though... experimenting with it until it worked right :)

Matt

[SupaJSK]

Unfortunately, i glued all my pvc parts of the durso together...doh!!

I'm up to 11/64 and still getting a sucking sound cuz the water level is too low i think. The water level also "flushes" sometimes...

I have a Mag18 on the return. Do I need to go bigger on the airhole or do I need to throttle back my return pump some?

[Bruddah Chrispy]

I did the adjustable cap thing, using a rotary tool. Now I can make fairly fine adjustments until the water level is right where I want it.

FWIW - I didn't glue any parts of the standpipe.

[pr0nd3xtr]

If the water level is too low, the hole is too small. Try going a bit larger and see what happens. I tried using a needle valve but could never get it right since it wouldnt let enough air through so I just removed it. What was funny was that the gaping hole I drilled to fit the valve was actually a perfect size for the flow I had.

Same thing was said in another thread here:

Durso Hole (http://archive.reefcentral.com/forums/showthread.php?s=&threadid=207485)

[vic8361]

I forgot what size the hole is but the hole will be differnt in each system depending on the flow rate. I just started out small and increased the hole as needed. It would be wise to buy a few caps just in case you go over board. There not that expensive anyway.
Vic

[ejmeier]

Instead of drilling progressively larger and larger holes, just pick the smallest drill bit you have and drill a new hole each time. You can get a more exact air flow that way.

PS - Going back to geometry classes, a 3/16" hole is NOT the same area as three 1/16" holes.

[tilua]

Dont worry if you drill a hole that is too big.. you can always use a piece of tape to cover it up.... and it is adjustable :D

Tilua

[ejmeier]

I was just saying that if you aren't using that adjustable air hole method, just drilling in the top of the cap, you can get a Durso the quietest by drilling small holes one by one. It is much more accurate to go from adding another 1/16" hole than to jump from 1/4" to 3/8".