u/Dc_vvvv

Hi everyone ! I’m in the middle of candle testing and my candle would burn fine and perfect , up until this point . When the candle is melted to half way of the tin, I noticed black build up on top of the candle wax. I’m not sure what I’m doing wrong … my hot throw and cold throw is perfect! But for some reason when my candle is burnt down to half of the tin, it does this . Please anyone help, if you have tips and tricks please let me know! ( the wax I’m using is coco apricot wax and 10% FO )