That was what I gathered from looking at people attempting mass mangrove export. Seen vids/threads of them being started, looks pretty but either no follow up or anything useful. Chances are it wasn't as successful as they hoped. If you want a display refugium, they are great if you mix other macros, between the stocks/roots.
In nature you find ecosystems between thier roots; macros, sponges, critters.
Properly built/sized algae scrubbers would prob be the most efficient export since that is what they are literally intended to do. Grow algae.
Can you post a pic or your sump?