Help! I cannot get my Egg (Medium size) hotter than about 250 degrees! I have tried both small amounts (below the holes) and larger amounts (above the holes) of charcoal with the same results. I've tried all combinations of bottom slider/top valve settings - having the bottom slider opened all the way, or down to 1/4", with the top all the way opened vs maybe having it closed, or just having the little holes open - but nothing gets us up beyond about 250 degress! I'm really frustrated! we wanted to try this Tandoori Chicken recipe the other night and it failed miserably - I need help, what am I doing wrong? The insruction book is vague, no specifics on how to use the top cap and bottom slider specifically to control the temperature...I'm about to lose my mind!