you can up those baffles if you need a deeper sand bed or increased flow but this there is bob fenners sump refugium design so......i'd stick with the plans i might use egg crate for the media and ...hang on i'll draw it up....
as it overflows the first baffle put eggcrate so the water has to flow through the carbon or whatenot....and high enought to where you can pull it out and put it in easily.