1. Based on those numbers, I wouldn't trust that test kit. AP is not a "high end" kit. The only kits I use are Salifert or Hach. Red Sea makes a good Phosphate kit. Here's a quote on phosphate levels:
"The optimal phosphate level, especially for reef tanks, is an immeasurable one, or zero, with 0.05 ppm-mg/l being acceptable, and an upper level of 0.1 ppm cited as well. Having a good, reliable phosphate test kit is important. FINS recommends Hach and LaMotte brands as being good choices. Sailfert seems to have a good, precise phosphate test as well, but from our understanding the Sea Chem scale measures too high."
I, personlly, think .05 is waay to high...but if the upper end they suggest is .1 ppm and you're reading 1.25 ppm, that's 12 times higher...Your corals would be dead.
2. I've got a used Phosban reactor collecting dust if you want it....$15.
3. I don't know anything about Phos-X and likely wouldn't buy it based on who the manufacturer is (that's my opinion). I only use Phosban, Salifert's media (forgot the name) or ROWAphos.