Using a power washer?
Answers:
What are you cleaning and why are you mixing chemicals with something as caustic and oxidizing as bleach? There are cleaners that can be used with a power washer that might prove just as effective for whatever you're cleaning.
Other answers:
Depends on what you are powerwashing obviously.
Depends on what you are powerwashing obviously.
do not mix bleach with anything. THe fumes can do bery very nasty things to your lungs.
should be ok
Just use water don't waste your time.