good points ice, I have never ran crushed coral so I was unaware of the detritus buildup but it makes since with the shape. I personally have always used an oolitic aragonite base with about half of the surface covered with pink aruba puka shell. I know that the texture affects flow but I just like the way it looks.crushed coral can be problematic, trapping too much detritus and contributing to high nitrates.
i use Old Castle/Southdown sand from Home Depot and have had no issues.
i think if i did not have that sand i'd either go with a nice aragonite or bare bottom.