I was told that this was a protein skimmer used for saltwater tanks. I'm freshwater only and know nothing about it. It came with a tank I purchased that the guy was going to convert to SW. This is a picture of it, I'd like to get rid of it but I don't know it's value or if it is missing anything. I know that there is a little piece that has broken off that my husband says he has. I don't know if it can be apoxied back on. The top of the skimmer says MTC, I went to their website and this picture is similar to the model HSA-250. Can anyone help with some information on this? thanks!