Oct. 16 How do you clean the bottom of the water tank? The buildup of gel-like mold-mildew is disgusting, and i've tried using a long handled, stiff-bristled brush with a beach-mildew cleaner, an anti-bacterial kitchen cleaner, etc. I can reach some of the gunk, but not all--- especially in the many teeny corners and crevices. This is awful No manual is needed or desired. We have that. AWFUL DESIGN! No real-life users consulted! Kathy