I never clean the media baskets in my IM Fusion 20 and it has been up and running for almost two years. I use it for a Coral QT and the parameters are more stable than my DT at the moment. I do not have any fish, just coral and a few inverts so that may be a factor, but the baskets themselves don't really get that dirty, but have plenty of life growing on them. i figure it's good because I can throw any coral in that tank and it will thrive. I have even taken coral that wasn't doing so well in my DT and put it back in QT to nurse it back to health and the tank is solid.
So, my vote is not to clean the baskets themselves, just change out the media when needed.