Hi, I have a love fish panorama 64l tank from pets at home and have Goldie's in. I am confused about the filter side of it though. The filter in it is a foam that is in a slot that goes into the filter box. There is also another foam that slots in behind it but in the middle of the foam it has carbon media. I have to replace this soon and have been looking about the internet to see if I can find something suitable but can't. Do you know of anything I can buy that will fit it?