Thanks for your last advise.
I found a extra high capacity rack 96 X 18 X 72 sold by Global for $231 which meets my specifications.
I'm using 20H tanks,4 to a shelf,that's a total of 96".
I will use 2 shelves for tanks and the bottom shelf for storage.
The Unit is 96" and each shelf is good for over 2000 LB.
My question is the 14 gauge steel is painted scratch resistant but not rust proof.
All my tanks will be covered and I will have a air conditioning/heat pump Mitsubishi unit.
The room was just made from a former ground level garage, 9' X 11'.
I'd like to have 3 of these units in the room.
It's either this or build the bulky 2'X4's which my wife[great decorator] does not like.
What do you think?