It MIGHT be normal.
You can measure the flow rate by timing how long it takes to fill a container of known volume.
The table here:
http://www.systemcooling.com/forums/...t=3685&p=31373
would suggest (bit of rough math in my head) between 2 and 3 LPM.
Keep in mind the storm design uses the water very effectively, and thus its better to have 3 LPM being effective than 6+ LPM in the old "channel in a block of copper" blocks.
I'd model it in my approximator but you use 3/8" tubing and I still don't model that right. Sigh.