Not to take anything away from TJ, but I bought the fluid discs from him and they did not work with my powder. With that said, all powder will not work in all media. I have seven dedicated powder cup colors. Out of the seven 3 of them have Tyvek media, 3 of them have vacuum cleaner bags and 1 has a brown bag. So this tells me and I have been doing this for along time, that all powder pigments are not created equal. I found this to be true with not only my powder but CSI (Pro-tec) powder as well.
On another note, vibratory movement as mentioned above is the key to a lot of problems. Since you are using an air source, let your air pump touch your fluid bed, the vibrations may help. Also you can build a small stand on your fluid bed that can sit on top of your air pump which will vibrate as well. A little ingenuity will solve many of your problems. Good luck.