First timer here with an ECB. Did the initial seasoning burn today. Was maintaining a solid 250 when I left. Came back 3 hours later from running errands and all but one small lump had burned to ash and temp was down to 150. Did I not have enough charcoal in the pan or is 3 hours just too long to go without adding any charcoal? FYI, this was lump charcoal, not briquettes. Thank you.