I think they are able to stay in buisness because most people that purchase them don't do research before hand. I also think some people liek them for the cost. And others like LFS
that use them well they have the time to play with and adjust them each day so they don't care. And becasue they have them work to some degree they then sell them and tell people they work because they want to make a buck. It is strange but I have seen these skimmers in a local store- on every tank. And the tanks were really awsome tanks. So go figure.