The exposure I always renew on 15 minutes.
The instructions on the package leaves to be desired! It sounds as if acting after 5-10 minutes and rinse 3 times with the spray ball is all done. In my second application I had indeed finally successful, but only with patience! The exposure I extended to 15-20 minutes, I had determined 40 - 50 times the syringe to really flush out the plug to get !!! (The ball has to be filled always complete, that can be tested by sets in the water and does not float above) For me, it succeeds only right if I keep the ball in a specific position). Then you're really relieved and everything works great and without pain in! But I owe only other testimonials and my great patience!