Hi I am new to this site. My name is Laurie and I have a question about something that we have in our tank. It is a piece of equipment and I thought it might be a carbon filter. It has a piece that sticks down in the water and it resembles water going in to this and looks like it might circulate back out. The problem is that it is real loud like it might need (I thought) carbon to make it run smoothly. Inside of it is a little fan. I hope you can understand this and I hope you can help. It is in a 10 gal. tank we have in the house. Thanks.