is a slope down overflow pipe quieter than straight down?
 

I'm putting up my 120gal tank. It's time to do some plumbing. I'm going to use a durso overflow.

I have dual overflow and 3 compartment sump. I can either have my overflow goes straight down to the left (skimmer) and right (fuge) side of my sump or have them crossed from left side of the tank to the right side of the sump and vice-versa.

Does it worth the effort to do it?
I'll have a 90 elbow at the end to a drilled pvc to slow down water flow. Should I submerge the pipe or have it half way seating on the waterline?

thanks

I've found in-sump durso style works very well. I have some bubbles that come out, but it's not too bad. As well, it is perfectly silent. I have 45's at the end as well. There is about a 1/8" hole in the cap.

what's a in-sump durso style?

Sorry, I forgot to attach the picture.

[img]http://mad-skillz.com/aquarium/12.16.2007-5.jpg[/img]

yes pipes draining on angles tend to be quieter then straight drops...

I'm curious Eric, why do you have durso's in your refugium? Are regular returns noisy?

Sure are lots o' pipes 'n hoses 'n stuff....

Do you use Dursos upstairs on the other end as well?

Jason

The dual standpipe method works better, FWIW.

You use a primary standpipe (no durso needed) which is shorter and has a valve all the way at the bottom outlet to 'back up' the water. This prevents the noise, bubbles, etc by adjusting the water level in this pipe. Then, you have the backup drain plumbed normally, with a standpipe that is taller than the primary. This is the backup/safety should the primary get clogged or need adjustment.

Its silent, its easy, etc. Much better than any stockman, durso, etc.

On my secondary, I utilize a 'S' trap to keep the water from falling more than 12" at any given time.... kind of like a weir or levy system to slow the water down and prevent bubbles.

Piping at an angle CAN help... it will slow down the water's rate of acceleration due to gravity, but if given enough height, it can still reach the velocity needed to drop in pressure and educt/suck in air bubbles as a consequence. This is why the 'S' trap system (although its not a sealed 'S'... there is an air inlet at the top of the 'S') or the dual standpipe methods are better. No stockman/durso/hoffer system can prevent the acceleration of water in the pipes, which is why the air gets sucked in, the noise starts, the salt spray spreads...

As water falls, it picks up velocity, and as water picks up velocity, its pressure drops as well, causing air to be sucked in. So putting a muffler on it doesnt solve anything... you will still end up with air being sucked in, noise either in your sump or in the tank because the velocity of air/liquid at the top will be lower than that at the bottom no matter what. To solve the problem rather than deal with it, you need to slow down the water's velocity.

[QUOTE][i]<a href=showthread.php?s=&postid=11575143#post11575143 target=_blank>Originally posted</a> by lakee911 [/i]
[B]Sure are lots o' pipes 'n hoses 'n stuff....

Do you use Dursos upstairs on the other end as well?

Jason [/B][/QUOTE]

Yes, I have one upstairs on the overflow. The other two tanks are direct connection off a bulkhead on the back.


[QUOTE][i]<a href=showthread.php?s=&postid=11574600#post11574600 target=_blank>Originally posted</a> by jtma508 [/i]
[B]I'm curious Eric, why do you have durso's in your refugium? Are regular returns noisy? [/B][/QUOTE]

As you can see, there are hardly any bubbles in my sump, and there is about 2000-3000 GPH going through there. The pipes not only remove all the noise from the water, but remove a large amount of air/bubbles as well. No salt spray or splashing either. I got the idea from [url=http://archive.reefcentral.com/forums/showthread.php?s=&threadid=1223445&perpage=25&pagenumber=3]Nanook's build[/URL].

Slow down water velocity is not the same as decrease water rate, is it?

I can't adjust the return pump flow rate to achieve slowing down water velocity, can I?

If I use a ball valve to slow down the velocity, do I add it just above or under the water line?

[QUOTE][i]<a href=showthread.php?s=&postid=11576217#post11576217 target=_blank>Originally posted</a> by hahnmeister [/i]
[B]The dual standpipe method works better, FWIW.

You use a primary standpipe (no durso needed) which is shorter and has a valve all the way at the bottom outlet to 'back up' the water. This prevents the noise, bubbles, etc by adjusting the water level in this pipe. Then, you have the backup drain plumbed normally, with a standpipe that is taller than the primary. This is the backup/safety should the primary get clogged or need adjustment.

Its silent, its easy, etc. Much better than any stockman, durso, etc.

On my secondary, I utilize a 'S' trap to keep the water from falling more than 12" at any given time.... kind of like a weir or levy system to slow the water down and prevent bubbles. [/B][/QUOTE]
by any chance would you have a diagram? your drawings are always outstanding.

If its the same cross sectional area, then yes, a proportional decrease in volumetric flow rage (gph) will be the same as the velocity (ft/s). The thing is, our drainpipes dont just transport water, they also tend to suck in air since as the water falls, it picks up velocity and wants more volumetric flow but it cant get more water. Since no more water is provided, it sucks in air. So from the standpoint of air and water combines, then no, velocity is not proportional to flow rate, since less water can mean more air.

When you add the ball valve, put it on the very bottom of the drain line, right before it spills into the sump.

Here is a simple diagram of the method... You really dont even need the elbows on the standpipes either.
[IMG]http://i90.photobucket.com/albums/k278/wetworx101/overflowpeg-1.jpg[/IMG]
The valve on the primary (shorter standpipe) goes lower, I just couldnt show it on that diagram.

This is a 0-edge style diagram, with how to make a check valve on the return that wont fail... but if you follow the drain lines, it will also show the method in use... valve at the bottom of the primary water line with backup standpipe...
[IMG]http://i90.photobucket.com/albums/k278/wetworx101/Howtodo0-edgepeg.jpg[/IMG]

I use the valve at the bottom of the primary drain set up and it works great. No noise at all. If you go this route make sure you use a gate valve and not a ball valve as the gate valve is easier to adjust. I have the ball valve on myn and I have to adjust it about once a week, basiclly every time I do a water change. But like Meister said make sure you have a back up drain plumbed higher than the gate valved like incase of blockage.

My 2 overflows are separated. I don't think I can do the primary and secondary drain as you shown. If I'm using 1 drain on each overflow, is it going to work when I have a ball valve just above the water line.

Would it be better if I connect the 2 overflows into one, then split to my skimmer and fuge compartments with ball valve on both end?

Let me know if it isn't good enough to give you a picture of what I'm talking about. I'll try to get a diagram up this evening.

I have a 3/4" & 1" bulk head on each overflow. I'm wondering if I can do the following

Left overflow 3/4" - Primary with gate valve at near water line
Left overflow 1" - secondary WITHOUT gate valve
Right overflow 3/4" & 1" as my return.

Is it doable? does it make sense at all?
Would it be better just stick with the 1 return & overflow on each side?

thanks

I just realize I can't really do this because water in the right side overflow will be stale. I guess that's bad.

Its not that bad. Its kind of a waste, as having dual overflows with this method is a bit useless, but if you changed the right overflow so that it has another primary (dual primary lines that 'T' together with a one valve to control them both perhaps and identical height standpipes), then you have the two 1" ones left, and the one in the right can be the return (1" is enough for 1500gph if you want), and the 1" in the left can be the backup standpipe. That way, the flow through both overflows should be about as close to equal as possible, and the right overflow will only be backed up if its primary isnt enough (gets clogged)... which should be rare if ever.