No problem with the silencer filling with water?
Unscrew the black nylon bolt and take the silencer off its base plate. Take it with you to a Home Depot or lowes and find the plumbing section. Get a small roll of Teflon tape and match up a thin o-ring to the diameter of the silencer cylinder. You can get it a little undersized (22-24 mm).
O-ring;
The o- ring will sit in the groove that the silencer tube sets into. Get a thin o-ring. Too thick and the threads on the bolt may not catch.
Teflon tape;
Cut off a 2 inch piece and wrap it around the end of the black nylon bolt that threads through the silencer into the base plate.
Your leak will be solved! Not everyone experiences this but I did and it worked perfect and was super easy to do.
Skimmer not performing;
1st, I would suggest investing in an ATO (tunze. Jbj etc.). Consistent sump level is vital to skimmer performance.
2nd, you state you are running it at 8 inches. I would suggest running it at 9 to 9.25 (if your sump allows). This way you can open the stand pipe more, allowing more tunability. From what I gather in reading your posts, your internal skimmer water level is set too high. If it's set too high, the initial foam head will belch into the cup prematurely and essentially knock itself down along with any promising results, then it will start all over again.
Do you see an air/water line in the skimmer when it's running????. Not the foam head!
This is the fine line that separates the bubble swirling water and uniform bubbles beginning to rise up the transition. If you can see it then I would suggest opening or closing your standpipe until you see that line at around 1/2 inch below the white collar that the cup twists onto. I you can do that, then just leave it alone for a day (no tweaking!) and report back.
Pm me if you have any questions. I will be out and about today but I will contact you as soon as I get a chance. This skimmer should not be giving you so much headache, so let us see if we can help.
Tivo