I use q-tips for cleaning the impellor housing - it says not to use metal in there right in the instructions. For the piping, I use tap water, since we are tossing all the gook out anyway you really are not leaving much bacteria in there anyway. If I am doing a water change, then I will use tank water to rinse instead of tap. I Only use tank water or treated water to rinse sponges and other filter media. I use Q-tips and my fingers to rinse the inside of the tubes and a good heavy handed smack on a hard surface to dislodge all the "buildup". A soft flexible tube brush if you want it perfect, I just want it to flow, so I leave some of the wall buildup on it. I know, that will make it build up faster, but it leaves a little biofilter in there too. Just my two-cents.