Nuriel said:do not clean off these items untill you have an established tank as they bacteria like to nest in decor crevices and such, and never clean the gunk out of your filter (maybe a rinse every six months in old tank water) as that is where the majority of helpful bacteria reside at.
hope that helps a lil bit,. good luck and keep up the water changes!!!!
You can clean the media more offten in a established tank. I clean it once a week, and I dont get any kind of ill effect.