I've administered two doses now, .5g distributed among all three of my tanks.
I decided to administer to all tanks because there was the risk that even though only one betta exhibited the symptoms, all had the potential to be infected with them.
So far, no fatalities, but the afflicted betta has been picking up just a little bit in its activity.
She exhibited signs of the white messy defecations. That was pretty painful to watch and realize, but so far i think i made a good decision in how to treat.
Only time will tell. Strangely enough, the males have all started bubble nesting religiously since implimenting treatement.