So I’ve seen it used before and I like the look and how it can get covered in coraline algae. Also being able to have a lot of flow without going bare bottom. I already have an established sand bed but is thin. anyone with some experience long term with this kind of substrate? also how would you go bout swapping it out? maybe a bit at a time?all at once? cover the original sand bed? maybe leave a thin layer of the original bed?