Mine is actually below the rim at this point so anything I have in the sand bed you cant see unless your standing and looking in. That's 1 reason for raising it up. My sand is relatively clean so I'm not too worried about that either. I'm adding it slowly as to not overwhelm the bio system in the sand. But I thi k by adding a deeper sand bed itll give is more cryptic zones for anaerobic bacteria to flourish.I think 3in would just look like alot imo well at least in my tank but I like 1 to 2in. I think sand beds are more work if u don't clean it every other week or so it's going build up with nastyniss. But I like them.