Dipping live rock

[Aquattro]

Originally Posted by Madreefer

Maybe I'm misunderstanding but I've always thought that live rock was an excellent source of a "natural flirtation". I've always kept lots of live rock in my sumps over the years. I won't use filter socks so there there is a build up of detritus in my sump. But all WCs are done in the sump and I vacuum it out with a shopvac every couple of months. I have about 75lbs in my sump right now.

Bill, yes, the rock is filtration, but the amount needed is usually far less than most people add. Between the rock in the display and any sand/substrate, you have more than enough bacteria to filter most tanks. Adding more to the sump isn't required. If you have 0 or near 0 nitrate, you probably don't need more filtration.
Also, the ability to filter nutrients is dependent on the porosity of the rock, and rock that sits in the sump tends to plug up quickly, and therefore becomes useless as a filter. Going one step further, it will eventually begin to leach nutrients back into the system.