Hi all. After using 2 piece ecigs for about a month and having lurked here, and watched many hours of YouTube videos I jumped right in and bought an Itaste MVP last week. I ordered a couple pro tanks, both of which had substantial metal shavings in the tube, which I cleaned out with cotton swabs. So, I filled a new pro tank with a clearish liquid last night. I vaped until it was about half empty at around 4 volts, which is within the recommended range stated in the guide that came with the pro tank. Before refilling, the liquid in the tank was clear, after refilling and screwing the bottom piece back on, the liquid turned a Carmel color, and every puff I take now has a distinct burned taste. Have I done something wrong? What can I do to prevent this in the future? Does the scorched liquid pose a health threat? Thank you for your help.