Main Herbie WB drain has a very small air suction --can't seem to fix it. Ideas?

[David3147]

Set up my Waterbox tank about a week ago. The main Herbie drain has, what I believe to be, a very slight air suction. If you listen closely you can hear the air turbulence intermittently and it will purge a bit more air every 10 minutes or so. This is an issue because it makes it impossible to perfectly dial it in to silence.

I have re-sealed and slopped more glue on everywhere I could and this helped (but did not eliminate) the problem. I even added some silicon to the PVC unions. Still the problem persists. The only thing I have not put any silicone on is at the bulkhead (But I did re-tighten it and it has no water leaks). Could it be coming from the gate valve? I may just replace the whole drain and bulkhead --but wanted to turn here first.

 

[Gumbies R Us]

Bumping your post!

 

[Dburr1014]

Were any O-rings are on those connections make sure the opposite area is smooth free of any imperfections. Also under the ordering make sure it's smooth.