I suspect that the reason why Russell and Conley parted ways was due to some disagreement involving preacher George N. H. Peters, whose work Conley backed up through Zion's Watch Tower Society; however, in 1883 Zion's Watch Tower journal criticized George Peter's work and recommended its readers not to purchase it. I suspect that Russell wasn't pleased with this endorsement of doctrines he personally didn't agree with, no to mention that Conley had broader contacts with the Advent Christian circles that Russell denounced often, and so he and his former patron parted ways. Conley went to become a leading member of the Christian and Missionary Alliance until his death in 1897.
Naturally, this bit of Conley's history is something that the Governing Body wish no Jehovah's Witness was ever aware of.
Eden