Well I'm trying my 1st smoke with my SNP just a couple of Fatties to get the hang of things, everything was going good the the smoker started cooling of It appears to have plenty of lump and I opened the vent up but it doesn't seem to raising the smoker temp, Should I add more lump?? or do I want to close the stack up some ??? If I need to add fresh lump do I need to light it with the chimney first???