My father is undergoing home dialysis where he uses 2 bags, no machine during the day & machine-assisted dialysis during the night. For the past 2 mo we have noticed that the fluid in the outgoing fluid is RED. His doctors dont seem to know what is happening, other than to say that blood vessels occasionally pop open and its nothing unusual. Can anyone direct me to links or provide information?

Yes. Check this site for some info. Hope it answers your question.
http://www.aakp.org/aakprena.htm