I use purple up, you have to watch though, it will spike your calcium. However, once I put on my Skimmer it was never a problem again. I simply check the levels about an hour before i want to add it and its fine. I have Healthy green, pink and purple coraline all over my tank and the green almost glows at night its so bright.
As they all say, if you can test for what your adding do so and add it slowly. The first day I added 5mL as per directions. I waited 2 days before adding the rest and tested all 3 days to see my level drops.
Should be noted that as your coraline & LR increases the more PU you will need. Im now at about 6mL a day just to keep it at 400ppm. 1 day without and im al the way down to 320-340ppm range. I went on vacation and should of had a friend do it, it was only 3 days but you saw changes in the coraline and the calcium was below 200.