Leech - What's going on?

So I was excited to play Chayula Monk because the idea of instant mana leech impacting both Mana and ES seemed like an awesome way to cover sustain and staying alive. But unless I am mistaken or just don't understand leech it doesn't seem to be working at all. I also got mana and life leech in equipment but I notice on gear it says it leeches Physical Damage while tree leech states it leeches Hit damage. And I am wondering if the tree is worded wrong and I am not getting leech because my damage is nearly all Ice and Chaos (and the chaos dmg nodes in Chayula do not impact the damage skills tooltip DPS so I am not sure if that is working or not either). Or Maybe 24% mana leech isn't enough to cover leech resist from enemies I really don't know.

Anyone know or have better luck with this or understanding with this than I do?