Question regarding arcane.

Hello mages

I have recently obtained the Molten Front vendor trinket 'Moonwell Chalice' and am curious as to when exactly I should be using it.

At the moment its being used with my burn phase along with arcane power and mana gem.
Would using it at another time prove to be more beneficial?
burn
I use mine during burn.

Mana adept actually remains fairly powerful even when your mana is low, and having that increased mastery during the burn will increase your damage even though you're not in conserve and thus not at full mana.