I am referring to this book: Исцеляющие мантры в Аюрведе
It is said, that according to Swami Sadashiva Tirtha if Dhanwantari Gayatri Mantra is chanted 21 times over the water, it becomes elixir, capable of healing most severe ailments.
My question is should the Mantra be chanted aloud (vachika japa) or mental chanting (mansika japa)? Is is also said that mansika japa is 10 time more effective then vachika japa, but is it OK for water?
Thank you!