How to improve my LS build

Im currently in act 2 merciless, lvl 62. Here are my stats:
~2700 DPS
~3900 HP, 140hp/s, but i run BM wrath and anger so that put me to about 3500.
~30% damage reduction, 45% with 3 end charge, and im planning to get 3 more with 2 passives and 1 from Oaks
~82% all resists with 3 end charge (i think my fire resist is slightly below max), ~-10% chaos resist
Here's my passive tree right now:

This is what I'm planning to get by the end of merciless:

Here's my gear

So here's the problem I'm facing right now:
-I have no dex. I like using fast attack speed weapons, as it boosts the elemental damage really well. I only have like 120 dex right now, and thats because i actively look for +dex gear.
-I run out mana quite easily. I run determination and purity, which takes up about more than half of my mana pool.
-I think my physical reduction is not high enough
I'm trying to find new
-1st priority: pure AR helmet with high life and IIQ/IIR, preferred with chaos resist.
-2nd priority: pure AR chest with high life, high AR, chaos resist, and maybe fire resist would be nice.
-2nd priority: pure AR shield with all resist and high life.
-3rd priority: new elemental belt with high life.

Is there anything else i need to fix? How do i improve my build

give your main skill ( in your case LS) a blood magic support gem, then it's done.
Plus, it's better to have LOH or LS to improve survivablity.

Your skill tree has elemental equilibrium in it. How are you making this work in a LS build?

My guess is that that passive doesn't do what you think it does, and you're nerfing your damage by a LOT by having it.