I not sure I buy the argument that power is cleaner at night. With the average working couple, all chores are completed at night. I would guess that dishwashers, washers and dryers, microwaves, and televisions all have increasingly more night use than ever before. Depending on your community, factories that run three shifts utilize the same electric use as in the day. When I owned the Monster AVS2000, the digital readouts indicated that the power fluctuated more at night - especially up until 9pm. I found the same up and down voltage at night on an older Tripplite 2400. Besides, the better line conditioning units should somewhat equalize the difference. I would love to find out if anyone actually has run an ionizer in the listening room and what effects if had if any.