"I am getting some bacteria coming out of my RO that I was not getting before. How can I clean the membranes."
You can use a product known as Minncare® or Oxonia. Both are sanitizing agents made up of hydrogen peroxide and peracetic acid. Dilute to 50 - 100 ppm, pump through RO, soak for an hour and rinse out. Please check with you membrane supplier and Minntech/Oxonia to insure compatibility with your RO membranes.