the polishing stone is not a stone but prolly that little white poly pad that gose on top of the drip tray. the poly pad just remove fine stuff from the water. when he say the prfilter he is prolly talking about the spong that gose in the over flow box. just an idea.
A 46 gal bow front (Soft coral) reef tank with a 10 gal sump. And a 30 gal (SPS and Clam) reef tank hooked up to the sump of the 46 so they share water.