Mana point regeneration

On a node, mana points regenerate at a rate of (Maximum Mana)*0.25 per mana pulse, which occurs approximately every 2 minutes.

Off-node, mana regenerates at a rate of (Maximum Mana)*0.15 per pulse.

Factors that affect Mana Point Regeneration

• Training in Elemental Mana Control, Spiritual Mana Control, or Mental Mana Control increases the rate of mana regeneration by +1 MP per pulse for every 10 ranks, rounded down. If a profession has two spheres of power (such as Empaths, who are both Spiritual and Mental), the bonus is +1 MP per pulse per 10 ranks of the higher Mana Control skill plus +1 MP per pulse per 20 ranks of the lower Mana Control skill.
• The spell Manna creates bread that, when eaten, gives a refresh-effect every minute. This refresh-effect includes a small mana regeneration dependent on the caster's training in the Major Spiritual circle. Manna can also increase maximum mana depending on Spiritual Lore, Blessings, which indirectly increases regeneration.
• The spell Heroism (215) gives a refresh-effect of 1 MP per minute.
• The spell Mana Focus (418) can change a room's nature from non-node to node for the purposes of mana regeneration.
• The Bard song Song of Power (1018) affects the mana regeneration rate of the room in which the singer is stationed.
• minor mana regen potions give +3 MP per pulse
• lesser mana regen potions give +8 MP per pulse
• greater mana regen potions give +13 MP per pulse
• Clerics and Empaths can MEDITATE in order to gain Spirit Points, Mana Points, Health Points, and Stamina at a faster rate. Clerics can also apply the meditative effect to other professions using a chrism gem. For characters with exceptionally poor Discipline and Wisdom, it is possible for meditation to decrease mana regeneration rate.

Reference

Official Magic Guide: http://www.play.net/gs4/info/magic-guide.asp#regeneration