I have the exact same tank and skimmer.. The over flow return pipe was annoying at first but now its soothing. If i don't want to hear it I just slide at zip tie up and its quite. Just remember to move the zip tie down again just in case return pipe dies and water doesn't siphon back into the sump..
Also it was quite hard for the drain pipe not to bubble.. I had to lower down the return pump and also made a bubble tower in the drain.. Still bubbles but it doesn't gargle and no bubbles into the DT.
Now I need to figure out how to clean the corner where the over flow is.. Getting kinda nasty full of algae. pipe is turning green.
Good luck man.. Hopefully I can help, if not there are A LOT of helpful people..