Skimmer or no Skimmer??

[BlueAbyss]

It will still trap detritus, even the finest of stuff, and will eventually cause you problems. Empty it and use it as circulation only, forget that it's intended to filter the water and pretend it's a pump. Trust me, and I'm sure someone else on here will agree with me.

The live rock will do you better in your tank, where it can both nitrify and denitrify. Forcing water through the rock like that will turn it into a biological filter, effectively eliminating it's ability to perform denitrification inside the rock.