Live rock in sump / carbon questions

[PCKRAJ]

I have 150 gallon reef tank with a 75 gallon basement sump(most of the time that room is dark)

1. Is it beneficial to have live rock in the sump? If so, should I have a timed clip-on light on the tank?

2. How long do you keep the carbon in the sock, assuming everyone uses carbon? I've been leaving mine in until I do a water change, which is about every 3 weeks or so.

Thanks

 

[naprestsleep]

1) As long as the rock is not causing buildup of detritus or blocking flow and causing dead spots I don't see the hard. More space for beneficial bacteria to grow. No light needed unless your trying to seed coralline algae on it. In darkness you may get more beneficial sponges and such growing on it.

2) I have a reactor and try to replace it every 2-3 weeks. More often when I have time. More often is not going to hurt anything except your wallet.

 

[tmz]

The rock will provide surface area for denitrifying bacteria and habitat for some cryptic criiters. No need for light. Big chunks are betterthan rubble since they gater less detritus( decaying material).

The recommendation for granulated activated carbon is 1/2 cup per 50 gallons changed out 1x per month( 1/3 cup if using rox 8). It can clog with bacteria and precipitation sooner in some sytems and simply kneading once a week or so it can free it up.