I have no experience with Algaefix, but I would be nervous about using that in tank -- so many corals rely on their internal algae for food.
As for Prazipro -- I have used it in a full reef tank with no issues -- including SPS, zoas, clams, S. Haddoni anemone, anemone crab, cleaner shrimp, fire shrimp, snails and crabs. (( plus other stuff I am sure I am forgetting. ))