The purpose for my suggestion is to determine whether or not water is being forced through the membrane during normal operation.I believe it is because when I unscrewed it and blow through it water was in the canister.
Hook it up, turn it on and see if water trickles out of the blue line closest to the membrane housing.
EDIT: blowing though without the membrane can tell us that the 2 ports (waste line and product line) aren't clogged. The membrane plays a crucial roll in how water is directed through that housing.
You can tell when the membrane is removed that there's not much to the casing.
Which is why choosing the right membrane is crucial.