The stuff I use is mixed with water. There's more to it, but you really need to watch the ph, you want it around 4.0-4.5. Lower will give you flash rust. The white powdery residue is from too long a dwell time or too heavy a coating. Section 1.2 of Tigers trouble shooting guide lists a few problems and correction suggestions.
http://www.tiger-coatings.com/filead...guide2_usa.pdf