Yes but turned down so it doesn't overflow with the cup off. I have an outside line on mine to keep ph stable. I put it back to normal at 8 days. If you still have a lot left at 8 days don't put it back to normal skimming yet.No skimmer for 21 days? Not sure thats really an option for my aquarium. Anyone ever run their skimmer while dosing this?
You have to decide what's most important for your system. You will be amazed that how your corals will perk up once that nasty stuff is gone. It swallows up all the nutrients that your corals would normally be taking in.