Current effect is 10% increased movement speed underwater. Very underwhelming especially considering the few zones it can be used in.
The movement speed isn't really noticeable at all.
Could this rune be adjusted to something more useful?
A few suggestions:
-10 to 20% more damage under water
-30% more movement speed under water
-2 damage reduction under water
or non underwater based
-mp regen is increased based on % of missing mana (90% mana = 1mp more per tick. 10% mana = 9mp more per tick)