Hello everyone & thanks again for help with my softener install about 2 years ago. All has been working great until about 2 months ago when after regeneration there was a lot of air in the water lines in the morning. It's gone after the first flush of the toilets. Also the brine tank was not filling but it was drawing. I read everything I could find & decided to check all fittings first, no change. Then I cleaned everything in the injector drain assembly (saw no dirt or debris), after that the brine tank was filling and drawing but still air in the lines. I left it like this for about a month with no change & still air in the lines after regeneration. I then replaced the air check, no change. I eliminated the float assembly, connected directly to the air check, still no change. I then disconnected the air check & held my finger over the brine draw/refill tube & when the suction built up it sounded like it was drawing air in around the valve body somewhere. Now I'm at a loss. One thing that happened at the same time this all started was Fire Hydrant flushing not sure if this could be the cause but thought it was worth a mention. Any ideas/advice would be appreciated!