Refugium Substrate? What do you prefer?

[jeremy]

I am gonna have a refugium in first section of my sump. Looking for recommendations on substrate.
The fuge will have several types of macro algae in it. And hopefully a ton of pods. I have had sand, mud, and bare bottom in the past and all seem to work well but want more opinions/experience on it. It's not gonna be full of Chateo to probably more display type macro algaes. I want it to be full of life.
So what do you prefer and why?

 

[jeremy]

I am gonna have a refugium in first section of my sump. Looking for recommendations on substrate.
The fuge will have several types of macro algae in it. And hopefully a ton of pods. I have had sand, mud, and bare bottom in the past and all seem to work well but want more opinions/experience on it. It's not gonna be full of Chateo to probably more display type macro algaes. I want it to be full of life.
So what do you prefer and why?

Please specify substrate depth and brand you use. Thanks.

 

[Maritimer]

I've got about an inch and a half of CaribSea's "Ocean Direct" sand in both of my 'fuges (HOB and in-sump), with another inch and a half or so of Fiji mud underneath it. I consider myself a total newbie, though . . .

~Bruce