Hi Folks, after watching a green aqua post on filtration it has made me realise that my external filter is not performing as well as it could. I have been using lava and a mix of bits and bats. I think this is the problem and want to replace with a very Porous ceramic media. Looking on line it’s hard to see how rough/smooth the media is. Please can anyone recommend the best products. Ideally ones that redo not have to be replaced regularly (matrix)