Skimmers will pull out praziquantel (some of it is undissolved when you dose it). Some antibiotics (tetracyclines) change the surface tension of the water and will foam up and be removed by a skimmer (but I don't usually use antibiotics in the water, better in the food or as an injection). Other than that, unless you are using adjunct ozone with the skimmer, I can't think of any issues. I run a skimmer on a 550 gallon quarantine system and only turn it off when its dosed with prazi.
Jay
