3M does NOT recommend that users operate at flows lower than the range specified in the corresponding datasheet.  The reason is at lower flow rates there is a potential for channeling to occur - where the fluid can find a 'path of least resistance' or channel that does not flood the entire shell volume. This in turn will not provide the expected/optimized gas-liquid interface/surface area... resulting in lower than expected gas transfer performance. This effect can be somewhat mitigated by orienting the contactor in a vertical position and flowing the fluid from bottom to top or vertical up direction, but we would still recommend staying within the flow range guidelines.