Temp drops when add charcoal?

[michaelandrews]

I have a char broil that I modified into a reverse flow, you can see it here. 

Right now, I generally light a full chimney and put it in the box to get things started.I then just add charcoal as needed on top. However, whenever I do this, it seems to drop the temp by 20 or 30 degrees. Should I be lighting charcoal in my chimney each time I add it, or is this really just a temp drop from opening the firebox?

 

[cliffcarter]

IMHO you should add fully lit charcoal. Adding it unlit is smothering your fire.