Delivery method — what the difference means.
The two machines take different engineering approaches to the same goal: raising dissolved hydrogen concentration in the bath.
Gas diffusion — Echo Revive
Molecular hydrogen gas is produced by the electrolysis cell and bubbled directly into the bath water via a diffuser. The gas dissolves into the bath water during the session. The Echo Revive delivers gas at 850 ml/min. The rate at which the bath reaches target concentration depends on the gas flow rate and the volume of water being saturated.
Closed-loop circulation — HERO Bath
HERO Bath uses a closed-loop circulation system. One hose draws water from your bath into the machine; a separate small internal reservoir holds distilled water, which is electrolyzed to generate molecular hydrogen. That hydrogen is infused into the circulating bath water, which is then returned to the bath through a second hose — continuously, for the duration of your session.
At 3,750 ml/min the HERO Bath moves more than four times the flow volume of the Echo Revive's 850 ml/min gas diffusion rate. Higher circulation flow means the bath reaches target concentration faster and hydrogen is replenished continuously as it outgasses from the bath surface.
Neither delivery method is definitively superior — they are different engineering approaches to the same goal. The flow rate differential is a factual specification that buyers can use to inform their decision.