For the record...
I popped my base open (finally) and got the see the innards the other night.
Based on the design, there is virtually no way this tank will ever shut down "zero air flow" even with the AFC ring completely closed.
Basically, there is no o-ring around the AFC ring. So whatever gap is between the AFC ring and the bottom will always be the minimum allowed airflow. Unless you get creative with tape, silicon, etc...
Here's a pic of the insides for anyone interested... I think we're way past "Please don't post pictures of the disassembled deck because cloners..." If I opened it while trying not to destroy it, I'm sure the cloners have no problem doing the same.
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