What size Air Pot?

[ceosam]

Going to give Air Pots a shot this round. I read a 2gal is really 1.2gal of medium, but even normal pot sizes don't match the liquid volume so I'm confused.

For those that have used... what size should I get for 16 on a 4x4 tray (coco)?

 

[Granger2]

2 gal. -granger