Ok Pedro, here's the thing about phals. If you dunk the whole plant it's going to get moisture in the crown and then will develop crown rot and eventually die. If you still want to dunk the whole thing after that dire warning, you'll need to either hang the mount upside down so the water runs out of the crown or blow it out with condensed air or use a paper towel to absorb all the moisture in the crown. As far as rooting hormone goes, yes it would be a good idea. I use K-L-N rooting concentrate. If you need a source pm me and I'll give you the name of the vendor I use. Good luck!