Nuflour has been the most effective for us this year. We did everything "Right" but a few things late, lol... We use the following tools~
IBR vaccine
Pinkeye vaccine
Fly tags
longrange
CHS Ultimin 12:6 with IGR
Dust bags
Started giving Endovac (Salmonella) vaccine. Vet recommended trying this as it is gram negative I believe? Anyways the long and short is by boosting the immune system for gram negative, you seem to get an inadvertent additional boost for pink eye.
And round them up and use Cylence if we see issues. We were late on the fly bags and fly tags this year. So, we got the fly bags out, and used silence as well. That got it pretty well in hand until we were able to run them in and give fly tags. It was just a bad spring/earl summer according to the vet.