Hello, I have a IM 30L AIO and I am not utilizing the back chambers for anything at the moment. Should I stuff the back chambers full of rock or is it better to have the extra water volume? I am not running any kind of mechanical filtration other then filter floss ATM. Toying with the idea of getting a skimmer, but not sure I need it. Curious if I could see benefits from more rock or if the extra water volume is more important to health. Thank you in advance for any information you may provide!