Other then hitting the foodtimer again when they restart I can't think of a way. That is a good one though, it would make sense but in Europe they generally don't do water changes very much. In fact the filtration systems were developed around a pressing German law that was going to severely restrict marine aquaria back in the 80's because the disposal of saltwater was seen as a pollution problem so it is generally frowned upon, that is why you see all those fancy skimmers and denitrators.