Wanna make a good deep sand bed

[Aquattro]

Don, I would have gone primarily with the sugar sand if you're only adding 2 or 3 inches. IMO, this would give you greater denitrification. Now that you've added the seaflor, you can still add some finer sand. It will tend to work it's way to the bottom of the DSB though, leaving the coarser stuff on the top. This could be good if you're planning heavy flow in there. In the end, whatever works and looks good to your eye is what matters.