Originally Posted by
Akeber
You're really off base here. The size of the heals you receive has nothing to do with mana gained, as only effective heals qualify for spiritual attunement. If your health bar is full and you get healed, you get no mana. If your health is down 5K, and you get a 20K heal, you still only get mana back from the 5K effective heal.
Disc priest bubbles can have a small detrimental effect, but most of your mana return in heroics should come from blessing of sanc and proper divine plea management, which is basically pulling packs fast enough that it never falls off.