You should rinse all the media before putting it in the canister. When you turn on the canister it will could because of the small media fragments that have broken off of the bigger pieces, so for a bit it will remain like that until it all gets trapped by your mechanical media (sponges/foam).
Don't use any 'polishing' media...it's too fine for your application. You'll be cleaning it out far too often. Run the normal course foam and then as many ceramic rings as you can fit (bio-media) in the rest of the filter. You can also put a foam prefilter on a power head and use that on the intake hose to your cannister (as I suggested on another thread.) to cut down on the cannister maintance and boost the cannister preformance on partially filled tanks.
Rinsing MECHANICAL filter media (foam) in the sink is just fine in fact your much better off doing it that way. BIOLOGICAL media on the other hand. (ceramic rings and the like.)
should never be rinsed off at all. If you have a huge build up of slime (BB) on your bio-media then you don't have enough bio-media for your system and you need to add additional capacity.