I think a pinch valve is going to be far superior to the FZONE solenoid and check-valve setup. We’re still seeing a little bit of backflow even with two check valves in series. Unfortunately the check valves that @RobJ and I found were all either really expensive, or required really expensive shipping from Japan. We’ve been discussing this offline, but I thought I should put it our here too:
A pinch valve should only require a solenoid (widely available and affordable) and some plastic parts (hopefully easily printable). How do we determine if a 5V solenoid (that could be directly actuated by the Pioreactor) would suffice, and whose up for designing an open source plastic pinch part that works in a normally closed orientation?