I really appreciate the Whisper canister filters. When I first saw them I thought, "no way is this gonna work". I now use them in all of my newt set-ups. They are truly powerful little filters, and you can customize the filter media. I put a foam pad (cut to size) in the bottom, fill the middle with charcoal and top off with another foam pad. You can also use the intended charcoal pouch, and then stuff the bio stars in front of the canister. At times I have wrapped a thin foam pad around the intake grooves to keep the larvae, or fry, from being sucked up. They are also inexpensive.