I have a phal-type den that refused to bloom for me for 2 years. I finally set it in the brightest spot on my porch and basically said "bloom or fry". Reason won over and it gave me blooms.
Since then, I've really pushed the light on my phal-type dendrobiums. I put them outside in the spring and summer and they get full morning sun and bright shade the rest of the day. The leaves are bright apple green, which is an indicator that they're getting the light they need/want. I don't bring them back in until the night time lows are consistently around 50-55 F.
I've tried the Epsom salt mix and it seems to work on my stubborn phals. I usually mix in 1 Tbsp per gallon of water, place the orchid in a large bowl and water with the entire gallon. I then place the orchid in the sink and water again with the water from the bowl so that the orchid gets 2 good drenchings with the solution. Set it back outside in it's sunny spot and repeat in a week. After that, I water as usual and most of the time I get spikes within a week. Don't know if that will work on a phal-type den, but it works like clockwork on my phals.
Give it a try, and really push the light limits on it...hopefully that will work. Good luck!