![PST HP100 Steel Tank | ScubaBoard](/e69yszg/727.jpg)
PST HP100 Steel Tank | ScubaBoard
With PP blending a higher end pressure (3500psi) will require correspondingly higher initial fills of both He and O2 from your supply tanks. It will draw them down below a useful level quicker. So you will need more of them to cascade and still end up giving a lot of unused gas back to the supplier.