RO/DI Units vs DI Only?

[Son Of Skyline]

Is there a significant benefit to corals and fish in using RO/DI vs a simple DI water filter? I'm trying to see if I can justify the cost of an RO/DI filter vs just keeping my simple DI filter. Will my corals suffer in the long run from not using RO filtration? I haven't had a major algae problem that I can blame on water quality in the 1 year I've been keeping reefs. Thanks in advance