I have purchased bad skimmers, had to upgrade my lighting and now I am getting rid of my powerheads and I bought a tunze stream that will replace the powerheads and wavemaker. If you run a sump then there are a lot of good skimmers out there. There are good (beckett skimmer, Asm, Euroreef and other major brands), bad skimmers (no name cheap brands, seaclone, skilter) and O.K skimmers (Nautilus, red sea berlin, Bak paks). Many more are out there. lighting which is easier to get a little more then have to buy a whole new setup. And one of the most overlooked things, Water movement which totally depends on each individual tank(what size, shape, and what is in it).