The return of the GURGLE, belch Durso!

[saltman1968]

A few days ago, I posted about my Durso pipe in my RR 90G bow. The tank has been set up about 2 1/2 weeks. I am running a white flex hose directly to sump with a Mag 7 return to the tank.
every few minutes there is an "explosive -propulsion" and thrust of water down the durso thru the flex hose into the sump, causing a belching.
I received some fantastic advice from this forum (to lower the durso). This was based upon the fact that the water level in the return area dropped precipitously right before the "belch".
NOW, with the lowered durso, I am still getting the belch... it has returned!
it is now positioned about 3 inches below where it was in these photos, and there is a very nice waterfall into pipe enclosure area now.
Pic's below...thoughts welcome!

 

[viper_930]

See that little hole at the very top of the durso? Drill it bigger. Done

The gurgling and belching is because the drain fills up with more and more water until it starts a siphon, pulling water faster from the overflow until it finally sucks a whole lot of air in at once. Typically the hole at the top provides a vent for air to go into the durso and prevent the siphon but since it's too small it doesn't work. Opening the hole will allow more air to enter.

 

[saltman1968]

How much bigger? enough to fit a pencil? now its about large enough to slide some clear airline tubing onto it.
why is it made the size its made if it subsequently needs drilling? does everyone eventually need to DRILL?

 

[teresaq]

mine does that when the hole at the top gets clogged with salt. I have to clean it about once a week.

 

[blackaero1]

Clean out teh air inlet on teh top. Mine does this when teh airline gets glogged with salt creep. Once clean all is well. Myt airline extends below teh water inlet on teh stockman I use and I only have to clean it about once every other month.

 

[saltman1968]

there is no evidence of salt creep either on the durso, or anywhere else on the tank (this set up is only 2 1/2 weeks old).
Any word on drilling the opening wider? And how wide to go?

 

[viper_930]

Drill the hole bigger until a siphon no longer builds in the drain.
Not everybody has to drill it. More water flow through the durso requires a bigger air vent, that's all.