There are three different views held by scholars in regards to salaatul tasbih.  One group considers it as recommended; another group considers it as simply permissible; a third group, however, considers it as an innovation without any basis. I am inclined to adopt the third view. I have explained my reasons for endorsing this view in my answer to the question#73 posted on this site; you may refer to it, should you desire to know the details.