If its new, I would keep adjusting the air going in. The noise is most likely the intake having a small opening, but the pump is creating a strong vacuum.
As far as the mod, its super easy and can be done for a few bucks. All you need is about a foot of air tubing and a valve.
Open the bottom of the skimmer. Take out the pump and disconnect the air hose.
Take your new air hose and connect it to the pump where the old one was.
Now take the rubber grommet out where the cord was routed.
Now take the air hose and route it throught the bottom and follow the power cord out. Replace the skimmer bottom.
Now take zip ties and connect to power cord.
Then put valve on the end of the hose.
Then turn it on and be surprised. It will bubble like crazy. Then adjust accordingly.
If you want a co2
scrubber. Put a small gatorade bottle with a hose connection in the top. Poke holes all over the bottom and hang it on its side. Fill with soda lime. This scrubbes all the co2
out of the air before entering the skimmer. So your ph stablizes.