After sinus surgery – my surgeon recommended daily sinus irrigations which I do. He says I need to use a new irrigation bottle every 6 weeks because

After sinus surgery - my surgeon recommended daily sinus irrigations which I do. He says I need to use a new irrigation bottle every 6 weeks because a bacterial film develops on the inside of the bottles. He says the film cannot be removed with regular cleaning. I would like to purchase more empty irrigators but you dont seem to sell them any mor