Thank you so much Big Dave! You are exactly right, I have NOT reached shock level once, not once, in spite of all the chlorine I have used. This link shows my most recent attempts to do just that: http://www.flickr.com/photos/50351313@N03/7260036226/

Thank you for giving me something to try to get a clearer test result. I'll follow it and post the results as soon as I can.