which is quieter for drain?

seagirl · 02/24/2007, 03:52 PM

My 75 gal has a 2" bulhead in it, i will use durso, but was wondering what type of plumbing would make for the least amount of noise. here is a picture(not too good ) of my 2 options. it would be easier for me to use the flex tubing b/c i already have it and it's easier to route, but i can do the PVC if it will be better.

also i want to have the end of the return under water(in sump) so i don't get any splashing noise, do i need a hole above the water line to for air so it doesn't flush

thanks for any help

McCrary · 02/24/2007, 03:55 PM

I use a durso and hard PVC plumbing with no noise issues. The drain line is under water and I use a filter sock to help with microbubbles and to catch any detritus.

BONDQ · 02/24/2007, 04:01 PM

The quieter drain will likely be the solid PVC. You'll have less flexibility but the pipe resonates less than the PVC, in my experience.

You will need a hole at the top of the durso to eliminate the "flushing-toilet" effect of your drain.

This occurs when the amount of water you are draining EXCEEDS the amount of air required to maintain flow, and your water backs up momentarily (gasping for air) and then FLUSHES down in a rush.
You will know this is happening as your overflow will drain rapidily and then you'll hear a flushing sound as air rushes down the pipe when the water level is low. All of the sudden the water will backup and the cycle will repeat.

It's easy to think of drains as just carrying water, but they also carry air down with them, and this is needed to maintain the flow of water and keep it in balance.

You can eliminate the flushing effect by increasing the air hole size until your achieve a balance of air and water going down the drain at the same time.

A 2" drain will likely require an airhole of at least 1/8", maybe more depending on the back pressure on the outlet (from being underwater). Just start small and increase the hole size until the flushing goes away.

seagirl · 02/24/2007, 04:10 PM

i did plan on the air hole in the top, but i didn't know if one was needed on bottom too. thanks for the tips on hole size.

RocketEngineer · 02/24/2007, 04:22 PM

Instead of the two 90s towards the end of the run, you may want to use two 45s as they have less flow resistance.

02/24/2007, 03:52 PM	#1
seagirl Registered Member Join Date: Feb 2007 Posts: 1,130	which is quieter for drain? My 75 gal has a 2" bulhead in it, i will use durso, but was wondering what type of plumbing would make for the least amount of noise. here is a picture(not too good ) of my 2 options. it would be easier for me to use the flex tubing b/c i already have it and it's easier to route, but i can do the PVC if it will be better. also i want to have the end of the return under water(in sump) so i don't get any splashing noise, do i need a hole above the water line to for air so it doesn't flush thanks for any help

02/24/2007, 03:55 PM	#2
McCrary Can't Stop Time Join Date: Dec 2005 Location: Tucson, AZ Posts: 3,079	I use a durso and hard PVC plumbing with no noise issues. The drain line is under water and I use a filter sock to help with microbubbles and to catch any detritus. __________________ Matt Patience is the best remedy for every trouble. Titus Maccius Plautus (254 BC - 184 BC), Rudens

02/24/2007, 04:22 PM	#5
RocketEngineer Space is big. Join Date: Feb 2007 Location: Maryland Eastern Shore Posts: 3,226	Instead of the two 90s towards the end of the run, you may want to use two 45s as they have less flow resistance. __________________ -RocketEngineer "Knowledge is what you get when you read the directions, experience is what you get when you don't." - Unknown Current Tank Info: None Currently

02/24/2007, 04:01 PM	#3
BONDQ Premium Member Join Date: Jan 2006 Location: So CA Posts: 621	The quieter drain will likely be the solid PVC. You'll have less flexibility but the pipe resonates less than the PVC, in my experience. You will need a hole at the top of the durso to eliminate the "flushing-toilet" effect of your drain. This occurs when the amount of water you are draining EXCEEDS the amount of air required to maintain flow, and your water backs up momentarily (gasping for air) and then FLUSHES down in a rush. You will know this is happening as your overflow will drain rapidily and then you'll hear a flushing sound as air rushes down the pipe when the water level is low. All of the sudden the water will backup and the cycle will repeat. It's easy to think of drains as just carrying water, but they also carry air down with them, and this is needed to maintain the flow of water and keep it in balance. You can eliminate the flushing effect by increasing the air hole size until your achieve a balance of air and water going down the drain at the same time. A 2" drain will likely require an airhole of at least 1/8", maybe more depending on the back pressure on the outlet (from being underwater). Just start small and increase the hole size until the flushing goes away.

02/24/2007, 04:10 PM	#4
seagirl Registered Member Join Date: Feb 2007 Posts: 1,130	i did plan on the air hole in the top, but i didn't know if one was needed on bottom too. thanks for the tips on hole size.