Anyone with advice on a dark refugium?

[yakfishin]

I have a 30G sump and seperate 30G refugium tank linked together through bulkheads. I'm new to this hobby and don't want to put any lights under my cabinet for the refugium quite yet until I'm comfortable with working with the rest of my equipment for awhile. I have heard of people having dark refugiums with no lighting, but there isn't much information I have seen concerning them. What can be placed in a dark refugium that will help out my system until such time that I may in the future add lights to it? What sort of critters will grow in the dark?
I would like make the best use of my refugium for now without the addition of lights. Thanks for your help.

[silverwolf72]

Just put live rock in it for the time. If you plan on adding lights it's pointless to set it up just to get rid of everything later

[Jocko]

Exactly. Put in live rock rubble now. That will give your system extra biological filtration power. Just leave plenty of room so you can stuff a bunch of cheato in there after you're ready to put a light on it.

[yakfishin]

Thanks for the replies. How about sand? What that do me any good in a dark refugium? Is it good to have sand if I'm growing
cheato, when that point comes?

[AquaReeferMan]

If you are going to add sand add a lot. You are looking for a deep sand bed. This houses your anaerobic bacteria, which will cut down your nitrates and turn them into gas for easy exchange.

[bertoni]

A thin layer of sand, maybe an ich or so, might be useful. That's as much as I'd add to a refugium. I don't use sand in my refugium at all, though.