Noisy drain to sump

[Leon71]

I've researched lots here and other forums to find out how to stop the noisy drain in my new setup. Just some history.

I have a Marineland 120gal with a corner overflow. The plumbing came with the tank and is a type of durso system. I have 1" bulkead through the bottom of the tank, followed by 1.5" standpipe and two 90° elbows at the top. The one elbow has two 3/8"-1/2" holes (one on either side) just above the standpipe, and a vent tube at the top. I can't get it to stop sounding like a toilet drain. So I replaced the elbow with a tee and cap. This seems to be common practice, so I thought I would give it a try. The top is now pretty silent. On the bottom I have 1" PVC straight down from the bulkead to the sump. With a union inline.

Now the problem. On both setups, I have extreme amounts of air coming down into the sump. I'm talking 2-3" high "boiling" in the sump. I've tried a shorter downtube (just at the water surface) and a longer downtube (3" off the bottom of sump, in 14" of water). There doesn't seem to be any change. Any help would be greatly appreciated. Am I overlooking something?

Thanks, Leon

[fishytime]

You said you capped off the top?.... If you did, you still need a vent hole.... Start off small and increase size til the gurgling stops

[Leon71]

Sorry, forgot to mention that I drilled a vent hole in the cap until the top became a lot quieter. Started out with 1/16" hole. Kept going until I had 2 holes at 1/8" and two at 3/16". Did I move too fast? Am I letting in too much air now? It seemed that until I had this many holes, that as soon as I put the cap on the overflow, it wanted to overfill the corner.

[Lampshade]

What i did to allow some "adjustment" was drill 3 x 1/4" holes through the side of the cap into the pipe it sat on. I didn't seal the cap on to the pipe, and could twist it to open/close the holes. worked out great until I put a high flow pump for my return, lots of microbubbles in the duroso set-up.

[Leon71]

I am using a plug, but that would work for adjustment as well. Will try that. Thanks. So if I get the setting up top right, will that cure the bubbles down in the sump? These are not microbubbles, but rather huge boiling effect.

[e46er]

Pipe running straight dOwn into sump will be impossible to get quiet with a durso standpipe

[Lampshade]

With a filter sock on the output you'll be fine for bubbles, I was running without them, so the bubbles freely travelled to the return. After lots of fine tuning the duroso was quite, the bubbles on the output where louder than the intake of water at the top. I swapped to a single herbie instead of my 2 duroso's, if you have that ability I'd recommend it.

Also, if the main input to the duroso is getting air you will have a loud bubbleing, i used a 90 and brought the intake down 4" under the water line, it was well needed, stopped large bubbles, only had smaller ones from the air intake.

[Leon71]

Thanks for everyone's help. Last night I made a "zig-zag" with 4 - 45° elbows and that reduced the boiling by about 75%. Still going to try a few tweaks to this and try to get it even better. Maybe play with the last downtube length and depth in the water.
Cheers, Leon

[mark]

started with Dursos, switched to Herbie due noise in the lines and gurgling in sump. No air, noise.

As for hole size with Dursos, I had 2 drains and flowing ~2000gph, in each cap, hole was only a little bigger than 1/8"

[paddyob]

You said you capped off the top?.... If you did, you still need a vent hole.... Start off small and increase size til the gurgling stops

Better yet... drill a 1/8 hole in the cap and add an airline valve. My drain is almost completely silent. If it bubbles I simply adjust the airline valve.

Here's a pic of mine.

http://i653.photobucket.com/albums/uu253/paddyob/e7b0166f.jpg