well not sure what you mean by "break it in", but I started mine right up after I got it. Dry skimming is when you set the skimmer so it doesnt pull out alot of water, and wet skimming is when you let it pull out more water. The super skimmer has been set up on my tank for 3 days and Ive already had to dump it twice...thats wet skimming. They are great skimmers!