A quick question: coffee turns green - safe to use for enema?

Hi,

Usually I am using reverse osmosis water for my coffee enema, right now I am on vacation and am using spring water (higher pH). I am still boiling the same coffee (Wilsons) in the same stainless steel pan, but somehow the solution is darker than usual and today when I boiled it a little longer it turned green. What does it mean? Is it still safe to use. The only thing I can think of is presence of minerals and higher pH of spring water vs my usual reverse osmosis water. Any thoughts would be appreciated.
Thanks in advance.