I just installed the BRS dual chamber DI to my existing RO setup. My old setup had dual DI chambers that sat on top of the unit, that always had water in them, making water or not. With the new BRS setup, when I turn the output valve on to make water, the dual chambers siphon all the water out of them. Is it normal that when making water those chambers are not full of water? Or do I need to purge the air out of them somehow? When I turn the output valve off they fill with water and the auto shutoff kicks in.