What kind of rubble rock works best in sumps/fuge?

[mmync]

I am building my sump/fuge and would like to use rubble rock instead of bio balls. Is there a certain type of rock I should use, and should I try to use rock with alot of coraline algae growth on it? And about how big or small should the rubble pieces be? And finally in the part of my sump/fuge where I have my dsb and macro algae should I put live rock in there also?

 

[broncofish]

I spread live rock rubble everywhere possible, overflow box, fuge/sump, kitchen sink(well not really). The best rubble IMO is the best live rock. I took a big piece of fiji and beat it with a hammer(good for stress, not good for wallet). Another big pro for rock in the fuge is it works as a great anchor for some of your really stringy macro.

 

[mr . salty]

I would agree that Fiji is probably the best.But instead of beating up on your expensive rocks yourself (ouch) try asking at your LFS for some.
Most have it and will sell it for a fraction of what the regular rock goes for.
Putting it in the overflow is NOT a good idea.As this could?WILL cause an obstruction and you will end up flooding the tank and your floor.
Also,looking for pieces with good coraline is not really needed for this type of application.Rock for this job doesnt have to be pretty at all,just good and porous for bio filteration....

 

[mmync]

What are you calling the overflow box? The part(chamber) in the sump/refugium that the water comes into from the overflow box of your show tank? Also is this the same box that usually has bio balls in them. Sorry for being a little confused