Too much air into sump w/ stockman standpipe

[danny]

I have a 125g tank with an HOB overflow (I know, drill it!) with two 1" "U" pipes filling the overflow. The drain is 1" and the flow volume is very good to the sump. The problem is that I get a tremendous amount of air into the sump and some "burping" in the sump. The overlow is not very noisy, I have the pictured design (basic stockman design) with the hole in the top cap, pretty standard.

The drain line into the sump is about 2" below water surface, vertical straight down from elbow. I had it at an angle, same problem. I had read 1-2" below waterline would be OK. This is all 1" PVC with (2) 45 degree elbows

Also, with this much air falling in the sump, my skimmer performance has degraded to next to no skim gunk at all. The skimmer sits in the same chamber as the drain. Not sure if all the air has impacted it's performance.

I don't have a picture, but one observation is that the entire stockman is not under water. The water goes about half way up the 2" sleeve that is over the slotted/drilled drain pipe. Should the water cover the sleeve, but be below the cap?

Gotta fix, micro bubbles becoming a concern. I have a piece of filter floss matt breaking the bubbles apart over a baffle, but not a long term fix.

Any thoughts? I'll try to post some pictures when I get home.

[danny]

Bump, any help on this?

[7designs]

I had the same problem so I went with the herbie overflow, works great

NEW plumbing method for an ULTRA QUIET REEF TANK!!!! LONG !!!! - Reef Central Online Community


Here is how I did it on my overflow box:
Silence that overflow box