LOUD sump/overflow

[jcardona1]

per Durso's site. also, i'm not sure if these are meant to be used with hang-on overflow boxes

Flushing Effect - Why does the water level go up and down?

Saturday, 11 April 2009 02:53
A commonly reported problem when first installing Durso 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 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.

The flushing effect works like this: Back pressure in the standpipe prevents air in the pipe from exiting the drain line. Instead of exiting the drain line, the air bubbles try to rise in the pipe slowing the rate at which the pipes drain. The water level in the chamber then rises. The increase in the chamber water level adds pressure to help clear the air from the pipe. Once enough water pressure exists in the chamber to overcome the back pressure, the air is literally is "burped" out of the drain line which crates a sudden rush of water. This is displayed as a rapid drop in the overflow chamber water level.
This cycle then repeats itself over and over as the back pressure builds and gets purged.

 

[jcardona1]

Sorry this is not a helpful response, but can I ask what's the benefit of the DIY Durso pipe versus just letting the water drain straight down and out the bulkhead? It seems like more work in comparison to just letting gravity drain the water out.

noise reduction. overflows are LOUD. my tank is 30" tall and it was LOUD with water dropping 30". the durso standpipes have silenced this tank completely. doesnt even sound like i have filtration, even with a 55g sump under the stand.

 

[dookietank650]

when i was setting up my wet/dry filter, i remember reading that every 90 degree turn in the hose is equal to almost a foot of head pressure. i made sure i had a constant downward slope without any big turns, and my cpr overflow would still gurgle. when i read the instructions (imagine that!), i simply had to adjust the overflow line in the tank as well as a vent tube in the bulkhead chamber of the overflow unit, the gurgle left and never came back

 

[Babyguppy]

http://forum.aquatic-gardeners.org/viewtopic.php?f=9&t=568&start=15

 

[Dane]

The slurp is from the intake in the tank and there isn't much I know of that you can do about that with the traditional DIY overflow design. The design I did does not slurp. I've never tried the durso but I have found that the standpipe only needs about a 1/4in hole to operate, so I put a rubber cork with a hole through it on mine and eliminated the noise.

 

[black056mtc]

There is your problem. The durso need to be more compact so it will fit inside the drain out box for it to works. Right now it act just like a suction device to transfer water from the left section the the right section then down. Need to mod it so the intake will be submerse and lower than the water level to the chamber next to it.

 

[Pharaoh]

Do you have a vent hole drilled in the Durso?

 

[redtailshark1]

USUALLY putting the pipe on a angle helps because the air and water seperate in the pipe

 

[redtailshark1]

did you build that overflow yourself

 

[MaddMaxx]

Wow, lots of replies while I was out... Thanks everybody!

per Durso's site. also, i'm not sure if these are meant to be used with hang-on overflow boxes

Flushing Effect - Why does the water level go up and down?

Saturday, 11 April 2009 02:53
A commonly reported problem when first installing Durso 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 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.

The flushing effect works like this: Back pressure in the standpipe prevents air in the pipe from exiting the drain line. Instead of exiting the drain line, the air bubbles try to rise in the pipe slowing the rate at which the pipes drain. The water level in the chamber then rises. The increase in the chamber water level adds pressure to help clear the air from the pipe. Once enough water pressure exists in the chamber to overcome the back pressure, the air is literally is "burped" out of the drain line which crates a sudden rush of water. This is displayed as a rapid drop in the overflow chamber water level.
This cycle then repeats itself over and over as the back pressure builds and gets purged.

Why wouldn't it work with a hang-on the back overflow? Just curious...

I think that loop is the killer, I see it causing that pulsing in the ovrflow drain, it looks like a wave machine when it really gets going. I tried a few different angles and they seem to help some, but eventually it just flushes again... I'm gonna keep messing with it, may even try to hard-plumb it for kicks...

when i was setting up my wet/dry filter, i remember reading that every 90 degree turn in the hose is equal to almost a foot of head pressure. i made sure i had a constant downward slope without any big turns, and my cpr overflow would still gurgle. when i read the instructions (imagine that!), i simply had to adjust the overflow line in the tank as well as a vent tube in the bulkhead chamber of the overflow unit, the gurgle left and never came back

I don't really know what you're getting at...

The slurp is from the intake in the tank and there isn't much I know of that you can do about that with the traditional DIY overflow design. The design I did does not slurp. I've never tried the durso but I have found that the standpipe only needs about a 1/4in hole to operate, so I put a rubber cork with a hole through it on mine and eliminated the noise.

Its not a DIY overflow, I only DIY'ed the durso. And the slurp is definitely coming from the the drain line leaving the overflow box, not the intake...

There is your problem. The durso need to be more compact so it will fit inside the drain out box for it to works. Right now it act just like a suction device to transfer water from the left section the the right section then down. Need to mod it so the intake will be submerse and lower than the water level to the chamber next to it.

Its actually not creating any suction, the water flows into the durso just like it flows over the top of the divider between the left and right. I don't think making it small will help...

Do you have a vent hole drilled in the Durso?

Yup. Think making it bigger will help? Durso's site said that a larger hole = slower flow, so I was hesitant to make it bigger/slower with my tank periodically filling...

did you build that overflow yourself

Overflow = no, it came with the sump.

Durso = yes.