To have the Purification Chamber working at its best, place any four Pokemon around the circle. Then, select a different Pokemon from either your party or PC. Move it over the Pokemon around the circle. When you move the new Pokemon over one of the ones you already set, see if the Tempo Bar goes up or down. Once it goes up, replace the old Pokemon with the new one. Keep doing this until you find the correct combination of Pokemon to make the Tempo Bar full.