Refugium substrate - sand, miracle mud, mineral mud, etc.

[luckycat]

I have a fuge ready to be filled with my substrate. My plan has been to put live rock, some lr rubble and algae (calupera or similar) in this fuge, but I'm not sure what substrate I should use.

Lfs swears by miracle mud, it seems like I can use less expensive products from CaribSea (mineral mud) for or Kent's similar product for quite a bit less $$... or go with straight regular sand.

Will the algae grow in any of these substrates?

 

[saltwatersmac]

Most I have read just use sand. That's what I'll be using.