As you can probably tell, I ended up going with pool filter sand. I really liked the black blasting powder from Tractor Supply but after stabbing myself on a piece of it, I just felt bad doing that to my loaches. Once it grows in you can hardly see the substrate anyway. I thought about a dirt/sand cap a lot - but in the end the amount of people saying they had trouble with replanting scared me off. I know I will be rescaping a lot as this is my first really big tank where I can afford to try things I wasn't able too before.