I think you are a bit confused over the PSI. Although your HPA tank can hold up to 3000 PSI, the output (actual pressure sent to marker) is only 700-750 PSI, which IIRC is roughly the same as a CO2 tank. Soooo, an Epic can run on either the HPA or CO2 tank without a problem.
But remember, Regular CO2 < Anti-siphoned CO2 < HPA.
Arrow Precision Sterling