Reduce noise of overflow into sump? Ideas?

[mpiermar]

Hello,

I'm back in the game after a 5 year hiatus! I re-did the sump for my 120, still using my Iwaki MD40-rxt. What has always bothered me was how loud the overflows are in the sump. All that bubbling/gurgling sound from the overflow discharge in the sump. The sump has about 8" of water in it, and the 3 1"pvc overflows drop in 1-2" from the bottom of the sump. The tank's overflows pull all that air in, and I can't seem to think of anyway to dissipate the air. Has anybody got any ideas? Or is that something we all deal with. I even have the pump throttled back, which helps, but I'd like to use the pumps full capacity.

Thanks for any thoughts.

Matt

[BLKTANG]

extend the drains into the water.

[sjames]

hmm, when I did that i found it even noisier, so i brought them back up just above the water.

I personally never solved the noise problem, my sump is in the basement, so i decided i could live with it.

[JonnyD91]

filter sock

kills the noise but more maintenance

[liquidlunch]

what standpipe do you use? i ditched my AGA one for a durso that can been made for $6. All the parts are at lowes. For me, the AGA and durso are night and day.
http://www.dursostandpipes.com/

[BLKTANG]

Originally Posted by JonnyD91

filter sock

kills the noise but more maintenance

that was my second guess.I use 4 100 micron socks,but clean them every 3 day's.I actually have an x-tra set so i always have 4 clean 0nes ready.

The cooling fan,& my Vortech are the loudest thing on my reef.N they aint that loud at all.

[hellbob]

The noise is due the air being sucked in right? Is there a way to stop that from happening, like a DURSO or Herbie? I have a single overflow split with two ball valves (would have used a gate valve) and adjust the two valves so that the overflow never pulls in air. Have it dialed in now so it's virtually silent. Lots of posts on the subject here on RC.

[uncleof6]

There is really only one way to quiet down, and eliminate the boiling bubble syndrome associated with air/water drain types (aka durso, stockman, and a few other gadgets supposedly designed to eliminate this inherent problem.)

The problem is caused by turbulence in the stand pipe, and this is the mixing of the air and water. In a stand pipe where the flow is laminar (separate, not mixed, not turbulent) the flow will be silent and there will be no bubbles at the output of the drain line. In this case the bubbles are not expelled, because the water is flowing down the sides of the pipe, with air in the middle, but the air is not moving.

The fix is a combination of reducing the flow rate, and increasing the pipe size. If you have a 1" air/water drain line, you are fighting a losing battle, and even Richard Durso states that a 1" durso is inadequately sized for all but the very lowest flow rates. A 1.5" durso, will flow < ~ 400gph non turbulent (laminar.)

There are a lot of physics involved with drain lines, and I won't go into all of that, but from the info above it is easy to see why there are so many problems associated with these types of standpipes. Although the pipe size is capable of handling the flow rate (and then some), the physics do not permit the stand pipes to flow that much, without the noise, bubbles and often reliability issues.

The cure, is to convert to a full siphon standpipe. A 1" full siphon, will handle up to ~1000gph without issues, up to a 1.5" that will go ~3000gph or more. A much wider operational bandwidth with just 3 pipe sizes, with no noise, bubbles or reliability issues*.

* There are other issues associated with full siphons.

The first being it is not "safe" to run a full siphon, with out a dry emergency back up, of the same size/capacity, in case the full siphon plugs, either partially-- or completely.

Also, since a full siphon is adjusted with a valve to match it with the pump output, variations in pump output, can also be an issue.

http://reefcentral.com/forums/showthread.php?t=1722515

Bubble can be an issue with full siphons, if the siphon lines are not air tight (whether they leak water or not -- venturi effect) or the inlet to the standpipe is too close to the water surface.

http://reefcentral.com/forums/showthread.php?t=1726126

Unfortunately, defining the problem, fixes, and cure-- does not always give a solution, especially with a running tank. Purchased "reef ready" tanks are also pretty far behind the times, in terms of drain system options.

There is much discussion (and debate ) about drain systems over in DIY, as this is a very common topic. It is of concern to everyone, as it does not do much good to get water in, if you cannot get it out-- without a hassle.

Regards,

Jim

[uncleof6]

Originally Posted by JonnyD91

filter sock

kills the noise but more maintenance

Originally Posted by BLKTANG

that was my second guess.I use 4 100 micron socks,but clean them every 3 day's.I actually have an x-tra set so i always have 4 clean 0nes ready.

The cooling fan,& my Vortech are the loudest thing on my reef.N they aint that loud at all.

Using filter socks, may to an extent be a bandaid solution, but it does not eliminate the problem. And brings associated problems in and of itself. Mechanical filtration is a carry over from freshwater aquariums, and due to the different nature, biology, and chemistry of marine systems, is not necessarily a good thing to use. This is debated, but is beyond the scope of this thread.

As far as maintenance of them, 3 days is too long an interval, with daily being the ideal. (same applies to skimmer cleaning.) The collected material, will cause a decline in water quality fairly rapidly, leading to higher nitrate and phosphate levels. But again, out of the scope of noise and bubble issues with drain lines.

Jim

[mpiermar]

Thanks all -

So I guess the only "real" solution is to go with a full siphon. That scares the crap outta me. It's been a while since I've looked at any of this, so I'll do some research into it. If I'm still unable, at least I can increase the diameter of the pipes...

Matt

[uncleof6]

Originally Posted by mpiermar

Thanks all -

So I guess the only "real" solution is to go with a full siphon. That scares the crap outta me. It's been a while since I've looked at any of this, so I'll do some research into it. If I'm still unable, at least I can increase the diameter of the pipes...

Matt

No reason to let them scare you. Siphons can be adjusted from a trickle to full blast (where trying to adjust a durso style is unproductive), and with also tailoring the pump output, can be set anywhere from zero to the full capacity of the pump and/or standpipe.

http://reefcentral.com/forums/showth...5&pagenumber=1

Jim