in the options screen there is a high flux yes/no option. what if any is the difference. i cant seem to find any. i know it sets the min ufr at 300cc/min yet if the goal is turned down it will go below 300.also if the if button is off is the uf actually off or does it go to a minimum. thanks in advance.

The high flux is basically a tmp "offset" to compensate for the larger coefficent of the high flux dialyzer. It avoids reverse tmp alarms by offsetting the tmp. There was a big problem with the "E" model fresenius machines that when patient who gained modest amounts of weight were dialyzed the machine would have a tmp alarm. The fix on those was to manually offset the tmp display when calibrating it. This is just a fancier way of doing that.

Also if the blood pump goes to slow the rate dropes to 300 (or 70 in low flus) do prevent hemoconcentration so that the blood does not become like molases