If it is new (e.g., within two weeks) then it may still be in the break in period and will settle in on its own. In general for skimmers, to reduce the output without replacing the skimmer you can raise the skimmer so it sits higher in the water, turn valve to limit air supply, turn down pump (if it is a DC pump), or get an insert to limit the interior size of the neck (if it is available for your model). or any combination of these. Good luck!