So it sounds like I'm looking for somewhere around 60gph. What do you suggest for substrate that will filter well? I had started to sway more towards just using coco fiber or tree fern substrate (I was thinking it may not stain the water?) and not having that layer of soil on the bottom. The tree fern substrate packaging says it's nutritious for plants but I'm slightly skeptical. And I'm going to grade the bottom a bit so I have more of a down hill stream. Should I just use substrate to grade it or should I actually angle the false bottom?