This was a tank i purchased predrilled and simply plumbed my system into. As I currently have it up and running I am happy with everything but this overflow. It is loud. With no intervention it has the very loud gurgling sound coming from it. It is simply an overflow box with the shown plumbing. I was able to quiet the gurling but inserting a small airline into the curve of the first bend. This stopped the gurgling but has a constant air drone from the inserted line. This is more desirable but it is rather loud with an inability to quiet it with longer line, one way valve, or baffling materials. Im fine with a water flowing noise, similar to a creek, but the air drone or very loud gurgle is unacceptable. How can I fix this.
