Overflow causing large air bubbles in sump

[Nerc]

Should my overflow drain be fully submerged in my sump? It's pushing out some large air bubbles. I've got bubble traps so my display is clear, its more about the noise and fear of back pressure.

[AliciaP]

I keep mine just so they flow into a filter sock. They are rigged up a little bit, laying funny so they don't actually go into the water because I can't stand those bubbles. It doesn't seem to be harmful, but I rather have the water fall our freely.

[Wharf]

I'm also new to the salty side. After loads of research i put my outlet about 2 inches into the water just about 2 inches above my live rock rubble. This has made my sump reasonably quiet. The live rock seems to defuse the bubbles and i don't seem to have any back pressure at all. Not sure if that's right? but seems ok to me.

[mfinn]

My return goes almost all the way to the bottom of my sump.
If your getting too much noise and bubbles, slow down the flow through the sump.

[Mavrk]

What size overflow and return pump do you have? Try reducing the flow from your return. I changed over to a Herbie and highly recommend it.

[OKDOHK]

My drainage is submerged goes into a filter sock. No noise and the filter sock will take care of any potential bubbles.

[Nerc]

I'm using an AGA Overflow Kit with a Mag 7 return. 1" drain 3/4" return

[jimmyj7090]

Try googling "reverse duroso". They are good for reducing bubbles, splashing, and noise.

[Nerc]

I should also probably mention I'm using vinyl tubing for my plumbing. It's all done very simple, 1" tube from drain straight to sump, 3/4" tube from mag7 straight to return. No way to adjust flow. I'm kind of at a loss when it comes to plumbing so I figured the simpler the better. The AGA Overflow kit height can be adjusted, though it didn't seem to do much other than lower or raise the amount of water in the overflow.

[Palting]

You can put the overflow pipe all the way to the bottom, just drill multiple large holes in the pipe that's under water, and there should be no issues with back pressure.

Noise control, however, is a different issue. There are several ways to diminish it, but you can never really get rid of it.

Least desirable would be to put a ball valve in the return pump, and valve the flow down until the noise is bearable. It works, but I don't like it because it cuts the flow rate down.

You can DIY a Herbie/Beananimal system. There are no bubbles at the main drain so there is no noise at all, but it does require quite a bit of DIY.

You can add a filter sock to the end of the drain to dissipate the flow and the bubbles. This would be the easiest, but that sock will need frequent rinsng and replacement.

You can also make a reverse durso, or make or purchase an overflow box that contains the bubbles and noise within an enclosed space. The enclosed space muffles the noise of the bursting bubbles to a low rumble. The AGA sumps have this box built in to their sumps, but I saw it for sale at an aquarium store as a separate unit that goes into any sump. Here is a pic of that built in box in an AGA sump. Water flows in from the top through that pipe with the multiole holes, turbulent water with lots of buubles comes out, then water flows out from an outlet close to the top of the box to a tray. That whole process occurs in an enclosed space, and all you hear is a low rumble. The return pump puts out 700gph at a 4 foot head, and that's consequently also the flow for the drains.
http://i851.photobucket.com/albums/ab71/Kalawing/Snapbucket/F1378D8B.jpg

I wouldn't be worried about vinyl tubing. Using vinyl tubing is indeed simple, also very convenient and easily changeable, and you can also make all kinds of connections and even put a ball valve on it if you want. Just make sure to keep those clear tubing within the cabinet so they are not exposed to sunlight, or any kind of light for that matter. Light can make algae grown inside the tubing. No light, no algae.

Vinyl tubing is very versatile. Here's a pic of the simple drain connections for my 110 AGA FOWLR:
http://i851.photobucket.com/albums/ab71/Kalawing/Snapbucket/D2E8D1D2.jpg

Here's a pic of multiple vinyl lines, vinyl with ball valves that I considered for my 150 reef tank more than 2 years ago. Taken during the build, those tubings are now secured with clamps to their connectors and fixed to the cabinet securely with plastic clamps and holders:
http://i851.photobucket.com/albums/ab71/Kalawing/IMG_0073s.jpg

[Nerc]

Great advice and pics, thanks Palting! :D