Buy a cheap carbon water filter cartridge from home depot, the kind that fit in the typical undersink water filter canisters. the ones that work the best are the cheap ones that have rubber ends and the filter is carbon rolled around a plastic insert.
Plug one end and attach a fitting to the other end so the air inlet can connect to.
The filter cartridge I bought allowed 1/2" PVC fittings to snugly fit without glue. The filter connects to the beckett valve with vinyl tubing.
The filter cartridge acts as a muffler and the carbon inside the cartridge helps to scrub the air of any impurities before it enters the beckett.
My skimmer is virtually silent and the foam is much more consistent, not as prone to air quality issues.
