Jeff, I'm using the potassium nitrate that Motes recommends in their video at 1 tbsp per gallon. No phosphorus, as I also (sometimes) water with well water that has plenty of phosphorus. I fertilize as often as the rain allows in summer, usually every 5 days or so. Taper back as the weather cools to about every 10 days in winter, depending how cool it is. If it stays in the 80's until Christmas as it did last year, well, weekly fert was in order then.
In spring I use the MSU (Michigan State) formula for orchids which still has low phosphorus, but a little bit.
