so the filter comes with that blue sponge thing that fits perfectly im assuming goes at the bottom. i put it at the bottom and that bag of rock media whatever(i dont use it because i have my own mesh bag with that stuff in it and its not a round a blob) so thats all you get with it. what else should i put in there? i just stuffed a few rectangle shaped sponges in there between the blue sponge and the rock media bag though they dont fill the box just like the blue sponge that comes with it though. i tried cutting them to shape but fell short. try and try again i guess. suggestions?