Trouble with Fisher brand cartridge for Nanopure

[Donald Chun Kit Wong]

My supervisor just got convinced by a Fisher salesman to buy the Fisher 
brand replacement cartridges for out Barnstead Nanopure II deionization 
unit. When we opened the sealed packets, the cartridges, especially the 
one at the end, smelled like rotten fish. I guess that's the resin. But, 
the water that passed through also smell the same way. We've passed more 
than 10 liters of water through. The other problem is that the 
resistivity of the water went up very very slowly and never went above 5 
ohm even after about 8 hours of recirculating the water in the unit 
(power on with the outlet closed). The last thing is that whenever we 
turn the power off, air comes back out into the feedwater from the pump. 
This is in spite of the fact that water is slowing out of the outlet 
freely and after a whole day of recirculating with periodic water 
drainage from the outlet. My supervisor doesn't think it's those cheap 
cartridges, but I'm not so sure. Maybe we've been penny wise, pound 
foolish. Does anyone have any comments, suggestion, etc?
Thanks.
 
Donald Wong
Pathology
U.B.C, Canada.