What causes increased urine production after starting dialysis.

[KenMargie]

My husband has ESRD, has been having home hemodialysis for 9 months, and is listed for a kidney transplant.  After he went on dialysis his urine production slowed down to twice a day which I was told is expected.  For the last few days he has almost gotten back to his normal urine production.  I am cautiously optimistic that this is a good thing but wondering why now, what has happened to make this happen,