I purchased my Saje diffuser several months ago. I had been using Tranquility in my diffuser and was anxious to try one of the new scents. I loved the scent of Spa, so decided to try it first. Unfortunately, after the first day, I found an iodine coloured residue in the water tank - a bit crusty and hard to remove. I wonder if others have commented on that - wonderful scent but a most unwanted side-effect.