It says occasionally feed coral??

What exactly is occasionally?? Every day, every other, every three, etc.

And how often should I dose my tank with the trace elements?

 

what says that?
what kind of coral?
how big of a system?

 

+1 what coral are we talking about?

Occasionally IMO is maybe once a week

For dosing you first have to test your params for a few weeks and gauge what you are deficient in and that will get you on your dosing schedule to compensate.

 

As with fish I say feed as much as they take while keeping parameters good.

but for most corals weekly is plenty, and most will do fine with out feedings.

 

It depends on what kind of coral, TBH. Just like all fish are different and need different amounts of food, the same goes for corals.