has fresenius changed the new k's to pull up more bleach like the old H's use to. all my K's where manufactured before 2004 and only pull up bleach for a few minute and then recirculate it threw the system. I heard sometime ago that they where going to go back to the old way. has that happen? and how can i upgrade my machine to do this? Thanks

What version of software do you have?

You can change disinfection (to name one item) times in service mode, I have not worked with Fresenius K's in three years, therefore, I can not lead you the rest of the way. however, your Fresenius service manual should help you. If you do not have one, www.fmcna.com should help to complete the task.
Good luck with all your endeavors

3.12 on the functional board. So have they changed the disinfect cycle on new K's?

I have function brd. version 3.17 and 5.22 act. brd. version. On the H machines they drew up 180cc of bleach and sent it to drain. When the K's came along they would draw up 60cc recirculate then send it to drain. This usually resulted in "cottage cheese" in the drain lines of the machines and causing problems. In the 3.17 version it draws up 120cc and recirculates for 15 min. then rinses the hydraulics.

The 2000K machines (with newer software) were designed to reduce the amount of bleach needed for a bleach disinfect cycle.