The macros are currently growing in my display tank (I don't have a sump). They're in the back corner, so they get quite a bit of shade but still some light and they seem to really do well under the partial shade. I have a pretty intense light though, so they'd be fine in a sump with a less intense light fixture than my LEDs. Flow where they are is medium-low, but I had some in higher flow for a while and they were fine. They're really pretty hardy, so as long as the conditions aren't really extreme they should do fine.