With stacked 500+1000 gallon pressure storage which one should be on top?

[Aiken]

If I stack a 1000 gallon LP tank with a 500 gallon LP tank in series which one should be on top for maximum stratification and BTU recovery?
Also should I weld smaller ports(1/4"?) for temperature or other functions in the tanks @ different levels?

 

[Nofossil]

I'd stack them with the small one on top. If you're welding stuff, think about how to avoid mixing and turbulence when pumping water in and out. There have been other threads that have discussed ideas - pipes with holes and / or baffles to distribute incoming water with minimal mixing.

 

[mikegct]

1000 gallon at about 8 lbs per is 8000lbs plus the weight of the tank. I would keep that on the bottom also.