Lower ph in water for orchid plants?

I am looking for ways that are not harmful to orchids to lower my ph to around 5.7.I am getting a ''ph pen'' and trying to figure out how to analyse water breakdowns giving by my state agriculture dept. such as what is acceptible for orchids.Knowing that is a rather broad question because of the variety of orchids,is there a book that could be helpful? I am growing a large variety from cattlyas,phalaenopsis,gongorias,paphs.ph... etc.thanks for any suggestions-Lee

Lower ph in water for orchid plants?
You could mix your tapwater with rainwater or distilled water not only would that lower Ph but also the hardness, which in my opinion is the bigger issue when growing orchids. You could also try passing the water through some peat moss for a while, the tanins in it will reduce the ph to some degree. Usually Ph from tapwater is adequate for orchids but the minerals in the water gradually accumulate in the substrate and cause the roots to "burn", the solution here : simply water the plant with rainwater / distilled (very generously)once in a while to leach out the minerals