I have a question about my new SpectraPure ro/di. I've noticed that in the final canister (the one filled with resin), the water streams down the inside wall of the canister, but on the outside of the actual resin cylinder, pooling at the bottom. The level of water sitting at the bottom of the canister fluctuates. Is this the way it is meant to work? I'm just asking because I'm not sure if any water is supposed to be seen in the canister part itself, and it almost looks like teh stream of water coming from the top is leaking through a seal.

Yes, that's perfectly normal. Nothing to worry about. Much of it is dependent on water pressure and that varies, so you'll notice that sometimes it fills and other times it does not. You do have the appropriate water pressure now, right (50 PSI for these units)?

My lackluster city of Dallas water supply gives me about 45 PSI. I did the waste water vs product measurement and had to cut the flow restrictor down to 7 inches or so.

You have some air trapped inside the housing. It won't do any harm, but if you'd like to purge it:
With the system running crack open (unscrew) the housing about a 1/4 turn - just enough to break the seal. You'll see the water level start to rise immediately. When the water level gets almost to the top of the housing, cinch the housing tight - you're done.

Russ

You may also find the higher or lower your hose end is exiting the DI, the level in the canister may go up and down. This is normal and as Russ said you can purge it but chances are it will go back to the same again. No biggie since the water flows around the outside and up through the middle, so the middle has the water inside it.