if you use bleach you really need to dilute it a lot and make sure no trace is left over (rinse, rinse and when you think you are done rinsing - rinse twelve more times). I have never used bleach to clean my hydro equipment and even though the manufacturer says I can, I doubt I will. If your hydro system is really dirty use Hydrogen Peroxide. Do a search on here to see which kind you should use - in a pinch you can use what they sell in any store but you should have a better quality H202 for cleaning your stuff.
So far, i have been able to get away with just elbow grease and very hot water. I also run Flora Shield through the system before starting a new crop.