I've been playing around with anodizing for some weeks. The thing is, my results are fairly inconsistent. At different times, different voltages are required to achieve the blue right past purple at the upper end of the voltage range, right around 80V. Sometimes 81V will give me a perfect, deep blue, and sometimes I need to give a voltage closer to 84V. Lately, more and more, I seem to be getting "stuck" at purple, and my results just give me a washed out purple. It's like the metal doesn't want to budge past purple, and if I crank up the voltage, I get some washed out mess. Any ideas?