Durso flushing

[Moe_K]

One of my Durso standpipes has begun flushing.
The water level in the overflow drops below the intake on the Durso, then air gets sucked in with a loud flushing sound, then the water level rises quickly back to the normal level.
This process repeats frequently.

To try and resolve the problem, I covered the air hole on the Durso: no effect at all.
I pulled the bottom of the 2" drain line out of the sump's water. No effect.
I made sure the bottom of the drain line was sunk even deeper in the sump. No effect.
I pushed down on the Durso to make sure all connections were snug. No effect.

Both Durso's have the same sized hole drilled in the top.

Any ideas on why the flushing is happening?

 

[Aquadiva]

It flushes due to back pressure...try taking the top off the durso, ie adding more air. Covering the hole, I believe, would make it flush worse.

Are the two drain pipes to the sump connected?? Are they identical?? Is one longer than the other??

I hate plumbing problems...

 

[Moe_K]

It flushes due to back pressure...try taking the top off the durso, ie adding more air. Covering the hole, I believe, would make it flush worse.

I'll try it tonight.

Are the two drain pipes to the sump connected??

Well, they both join the same 2" drain line.

Are they identical??

Pretty much.

Is one longer than the other??

Nope.

I hate plumbing problems...

Yeah, they're not fun, but this one is pretty minor.

 

[delta]

I didn't like the drains connecting so I seperated mine. When I installed my reverse dursos I had a little flushing but it worked itself out after a day or so.

You may have some salt spray build up try cleaning out the hole and see if that helps

 

[MikeG]

Moe, sound like not enough air. Like everyone else said take off the cap or make the air hole a little bigger and see if it helps. I made adjustable holes by using a slip cap don't glue and drill a hole through the side of the cap near the bottom and make sure it goes through the pvc connectiong the cap and T. Now you can just twist the cap to adjust air intake.

 

[Mike75]

I had remembered seeing this on dursostandpipes.com, not sure if it'll help you any:

"Flushing Effect: A commonly reported problem when first installing standpipes is what I call a flushing effect. The water level in the chamber bounces up and down at a slow steady cyclic pattern. This is different than the issue above where the water level stays to low. This issues typically is not caused by the size of the air-hole in the end cap. The flushing effect is almost always caused by back pressure in the drain line. Typically the back pressure has two main causes:

#1 Drain pipes in the sump being submerged below the water surface to far. Ideally you just want the drain pipes submerged about an inch or two. Just enough to reduce the splashing noise in the sump.

#2 Any loops or dips in the drain lines if using flexible tubing. If using hard PVC pipe for the drain lines make sure they always have a slope to them, don't make them perfectly horizontal or perfectly vertical."

It looks like you've already taken care of #1.

 

[JohnK]

If it was quiet and now is flushing my guess is salt creep obstructing the air inlet. Mine need to be cleaned every couple of months.

 

[Moe_K]

Yeah, it didn't flush for the first 3 days, then it started.
I'll try removing the cap tonight.

Man, I don't want to replumb the drains.

 

[Richard]

Clean the vent holes it probly cloged due to salt spray

 

[Moe_K]

Freakin' salt!
I'm going to get rid of all of it.

 

[Aquadiva]

Freakin' salt!
I'm going to get rid of all of it.

Moving into guppies??

 

[Moe_K]

I haven't touched the tank yet, but the flushing frequency has dropped to once or twice per hour now.
WTF?

 

[JohnK]

Did you lost power at all in the last few days?

If so, that might have caused a slight increse or swelling or something with what accumulated salt creep there was. That way the air would be restricted a bit when the flow came back on, but after a day or two the water and air flow opened it back up? Just a guess???

If it's really sensitive to air inlet clogging, I bet you could go up a drill size on the vent hole to make it less sensitive but still quiet. An extra PVC cap is cheap and easy to swap out.

 

[Moe_K]

We did lose power for a little bit on Thursday. Good guess.

 

[JohnK]

Also try poking a small zip tie or something around the air hole, see if that does anything?

Does your sump level fluxuate or is it constant (auto top off)?

 

[Moe_K]

No auto-top off.
Sump level stays pretty much constant, though.

 

[JohnK]

Just thinking that if the sump level was up a bit it could have caused the problem mike mentioned above?

Did you try poking something around in the air hole? make any diff?

I just checked my overflows and had to scrape around the inside of the air hole with a tiny scissor blade to get it flowing smoothly.

 

[APISTOBORELLI]

I had the same problem until you started this thread. Earlier today I drilled a third 5/64 hole in the cap. Seems to be enough, it hasn't "flushed" since.

 

[JohnK]

My way to do it is to use a single hole just big enough to stick small zip ties into.

This way I can drop a zip tie or two into the hole (connector end up) to restrict the air if necessary and it's easy to clean. If it has too little air without a zip tie in the hole then I know I can go up a drill size.

Edit: just to add/emphasise - PVC caps are cheap and easy to change. Why not tinker with this part of the duroso?

 

[delta]

I just drill one 1/8" hole if it isn't enough I make it bigger. If it is too big the durso runs a little higher until the salt creep tunes the durso to perfection.

but I dont really play with them too much they always fluctuate at first until they get scuzzed up a little