From humblefish's thread
Prazipro is generally considered reef safe, although it may kill any tube worms/feathers dusters you have. It may also eradicate bristle worms. If you have mass quantities of these, the resulting die-off can lead to an ammonia spike. After treatment is done, activated carbon may be used to remove any residuals (if you need to use a different medication next). This is important because the Oxybispropanol (solubilizing agent) Prazipro contains will sometimes cause a bacterial bloom (cloudy water) when mixed with other meds. If using a protein skimmer post-treatment, be advised that it will “over skim” for at least a week or so.