I got a penguin 350 by Marineland. It seems to be working great but it releases a lot of tiny bubbles which makes my tank look very dirty. I unplugged it and my tank looked a lot cleaner. I was thinking that maybe that's how it's suppose to look like or that I need to change the pads? (The pads are kinda old) or is that just how it's like? if so I would just buy a new filter.