Substrate question for refugium

[Lefty]

Hey thanks for the help with the plumbing. I actually have finished and will be adding the substrate and water for a couple of weeks with nothing else in the tank. I have to make sure it works right??

Ok in my main tank 75 gallon I have decided to go with a plenum instead of the dsb. Several reasons, the guy who infected me w/ the reef insanity has one on his five year tank and I simply like the crushed rock look better than the sandy bottom, so hopefully I am not stirring up heated feelings.

My question is what should I use for my 15 gallon Refugium substrate...would just a 1" or 2" bed of rock be ok...or should I actually use some sand in a DBS approach? I want the refugium to eventually provide pods for my critters (eventually) and function as an algea filter.

My plan is to put my substrate materials in fill up the tank and just let it run for two or three weeks to iron out any potential problems...probably even engineer various power "outages" to see what happens and where the pitfalls are. Does that seem reasonable?

I will probably have more ?'s in a two or three weeks when I am ready to add liverock to the main tank...Should I start my refugium w/the main tank or allow the maintank to cycle before starting a refugium?

Thanks for all your help and suggestions.

I have a 75 gallon tank
15 gallon refugium
15 gallon sump containing the return pump and skimmer
I basically used the system shown here
http://inlandreef.com/Images/DIY/Plu...gium_plumb.gif

[Doug1]

Might as well test run it all the cycle every thing at once. As far as substrate in fuge, I would be inclined to say sand, but then I have a DSB in my 75

[RWD]

I would add sand to the refugium and not just rock. Sand will provide a place for pods and worms to reproduce and also help with nitrate reduction. IMO you will get more pods with sand vs no sand. Oh, good idea to run the system to find any potential problems. I'd run it with the substrates in it and also start the refugium. This will allow the sand to settle and the water to clear while you test your system. Don't know anything about plenums, never used them. Good luck, Bob