Hey guys. My tank is about a 90G freshwater tank for starters. We got it for a friend and it's had a custom built filter in it for the last few years but I think it's time I should get a new one, it's not doing a great job of filtering the water anymore (and it's not a great type of filter TBH). I've been looking at the external types of filters but literally have no idea where to start. As I said, its about 90G or 300L give or take. I've got a few small clown loaches, a few gouramis, a sailfin pleco and some bristlenoses in the tank at the moment. It does also have live plants in there, if that makes a difference. The current filter works around volcanic rocks but they are quite old now (10+ years) and just doesn't seem to be working, but that might be the way it sucks the water through or something, the whole setup seems to be dying. What would you guys suggest I look at? Thanks.