It is not safe to swim in a pool with a CC reading of 3.5. Sorry. I know that is not what you wanted to hear. Maybe if you can, test it again before going to bed and hit it with more bleach and then test/dose every two hours in the morning. See where you are at that point. Repost in the am and let us see how the numbers are going. Keeping my fingers crossed that you get past this quickly!