I purchased a used Palomino popup and have been testing out all the features. I went camping last week and filled the holding tank. The only thing in the camper that uses water is the sink which works fine. However, I forgot to drain the tank. There doesn't seem to be a way to drain it once the camper is closed up...at least that I can find. There are a couple different hose attachments on the outside near where the sink is located. It didn't come with an owner's manual. Do anyone know how I drain it? Is there something inside by the sink that I need to do? Any suggestions would be helpful. I'm going camping again in a few weeks.