Not knowing the NxStage system ... To be honest I don't know how they can get away with only having a filter system and not having a water treatment system of some type that better cleans the water of contaminants before it makes the dialysate. ...
That is one of the breakthrough technologies which makes the NxStage system so great. There is an outside filter which removes large particles. It occasionally needs to be removed and flushed. Inside the Pure Flow, is a "Purification PAK" which cleans the water of contaminates before it makes the dialysate. The Purification PAKs last several weeks and the Pure Flow tells you when it needs to be changed. IF I remember correctly, in addition to physical filtration, it uses ultra-violet light somewhere in the process to kill organisms which may be introduced with the household tap water.
I may be wrong about the UV light, but if that is the case, then it will be changed frequently when the PAK is changed every 4 to 12 weeks. The Pure Flow alerts when it is time to change the PAK
I'm glad you got some answers from NxStage and hope this will resolve your issues. Keep us posted.
I wasn't the one having the issues with the lab tech, but I wanted to know the answers to post here in order to head off the speculation that NxStage Pure Flow does not produce high quality dialysate.