Initially as complete newbie I didn't understand that it makes a difference in yield and went with 3 gallon fabric pots with FF soil. Now I want to upgrade to 5 gallon air pots with coco coir. I did my research and read that original brand Air Pots and that their #5 actually holds only 3.8 gallons and #7 holds 5.8 gallons. Essentially I would have to step up a size to get inside size to match my needs. For Ultra Oxy brand on HTG website description says 5 gallon holds 0.92 cubic feet which is 6.88 gallons. On Amazon I saw photo review of 5 gallon Ultra Oxy and it was claimed to be 3 gallon in size with 2 gallon bucket standing next to it for comparison.

That's why I am here trying to see if anyone has any direct experience with Ultra Oxy and if they also need to be stepped up to larger size. Does anyone know?