How do i choose the best gravel for my new aquarium? I am moving water and fish (parrot and african cichlid) from smaller tank but do not want to reuse old gravel. It's confusing to decide between sand, small or large gravel and what brand. I see Caribsea markets substrate that has necessary bacteria, but aren't i rinsing the gravel before it goes in the tank? So there is the Este's brand too and it says nothing about having good bacteria. SO do i need it with or without bacteria? How do i determine what size pebbles are most comforting to my fish? OMG