Supplements and RO/DI Water

[Hamsnacks]

So a few experienced reefers here in Town have been giving me a few coral (Mushrooms, Hammers & Torches..) and their tanks look amazing. To my surprise they're all using tap water.

I still plan on using RO/DI water when they finally replace the broken unit they sent me. But I had a question regarding Pure H20.

I understand all coral is different but a general question.

If I strictly use RO/DI water, does that mean I will have to add supplements?
One reefer said, "Why would I remove everything from tap water just to have to add it back in?" I understand cause it also contains other non-beneficial components. But

Will I be able to pull off most Coral strictly with Pure H20, Good Lighting, Water movement and Feeding of the fish, or should I be adding something like Kent Coral-Vite as well since the water contains nothing at that point?

Just wanted some clarification.

Thank you

 

[lapin]

You can use tap water provided it is free of chemicals and metals that might harm corals. Only tests will let you know what is in your water.
Using RODI removes all the stuff so you know its safe.
Water changes with a good reef salt will replace any removed stuff the corals need to thrive.
Until you reach a point that water changes can not keep up with your corals demand there is no need to add extra stuff (dosing)