How was she treated for the respiratory infection in the past? Was she placed on antibiotics previously? Sometimes its best to ask for a culture and sensitivity test from the vet with recurrent RI. It seems like when you can afford it this needs to be considered. If that is really what she has or is suffering from. The c and s testing can be pricey but it will tell you a lot. Good luck.Your set up looks really nice and clean btw.