I’m setting up a grey water system for my washing machine. I’m installing a vacuum break so the grey water drain doesn’t act like a siphon when my washer is filling. Which way should the arrow point on my check valve? I’m assuming down (towards the drain) so that it provides some positive pressure during filling. Just want to double check. Pictured is my vacuum break. The drain will run along the bottom of the T fitting. There will be another pipe section connected to the open end on the T. Thanks!