best way to stop bubbles in sump from overflow?

[kv69]

I have way too many bubbles from the overflow in to my sump causing salt creep. How have you guys fixed this?

 

[AlexStinson]

You can drill some holes in your pipe above water level to allow air to escape. You can also try to cut back your flow a bit, or maybe even cutout some acrylic to put over this area as a splashguard.
Also you probably shouldn't have the entire pipe underwater, I usually have mine go into a 90 elbow, that is about halfway below the water surface.

 

[kv69]

Thanks I'll give it a try. I made a Durso but didn't drill a hole. I'll give the 90 a try as well. Thanks.

I'm open to other suggestions as well..

 

[Bpb]

Reverse durso in the sump. Works wonders for chilling out the noise and turbulence.

Basically your drain line comes out of the bulkhead and into the water several inches. Install a 90 degree elbow and increase pipe diameter to 1.5". Now on the submerged horizontal section install a pipe with one or two T fittings, with vertical pipes with a cap and a hole big enough for airline. Put in airline and seal with epoxy. At the end of the pipe do another 90 degree elbow facing down to divert water flow to the sump floor. These vertical stand pipes accumulate 90% of the bubbles and noise from the overflow. Making the water much quieter and less churning. I run the airlines into an empty Gatorade bottle for pure silencing. My durso is just about as quiet as can be. You can hear a steady fizz from the tiny bubbles that make their way through. Basically the way a soda glass sounds after pouring.

 

[Bpb]

Btw...in that picture you see the pump was running. 500 gph. Through the overflow and the sump was that calm. Now this was with fresh water so salt water will allow some micro bubbles to escape all the way out, but you get the pictire

 

[mcarroll]

cut back your flow a bit

#1 best answer.

2x to 4x your display in GPH is all you need. That is actual flow rate not the flow rating of the pump or drain. Ideally measure the drain output with a bucket or other vessel of known volume - time how long it takes to fill the vessel. Convert your volume/time to gallons/hour.

You may already be there, but hopeully you'll find you have room to turn down the flow a little and eliminate the problem...or most of it.

Reverse durso

I do something similar with some 3" PVC drain fittings. Seems more like a protein skimmer (or skimmers) without a removable cup than a standpipe to me though.

@kv69, the idea is just to slow down the flow and give the bubbles a chance to settle.

Bigger plumbing (than the drain) takes care of a lot of this just by slowing down the water.

I went from 1.25" drain to 3" bubble-stopper. Higher flow rates (I'm about 3x) or larger drain plumbing may require larger sized plumbing on the bubble stopper for equal results.

Between the bubble stopper and designing an "ordinary" flow rate for the sump, I do not have issues with noise or bubbles and don't use any silencers on the drain boxes.