How long should i wait to add fish or coral or inverts??

[Doug]

Wet/dry filters create nitrate. They remove nitrite and ammonia, but only once the bacteria is established.

I would never add livestock to a new reef tank, for at least a month and then slowly after that.

If livestock is already added to a new tank, the biological capability of the wet/dry or liverock or sandbed, is still to low to support them. A slow build up of ammonia and then nitrite will harm the occupants. If this is the case, they need large regular water changes, until the cycle is complete or removal for now.