When it comes to red slime and dosing your tank, I am a fan, but I know some will disagree with dosing altogether. I have had Red slime, and I dosed with RED Slime remover----yellow powder you add to your tank, then cycle out in a week with a water change. It killed all the red slime, never harmed any of my corals or fish. As a side note after you use it....feed your tank only every other day, or less, and this will control algal blooms of this sort.
Here is a pic of the stuff: