[2.2] Acrobatic Knives - Assassin - Ctri EK/MoM/Phase Acro/VP, Ascendancy skill tree updated.

Not sure you meant mana pool or mana regeneration, but no trick for both of them.
you can find '+xx maximum mana' on rings, amulet, shield, gloves, and Mindspiral offers at least 100 mana.
'xx% increased maximum mana' and 'xx% increased mana regeneration rate' from skill tree, jewels, rings, amulet, shield, wand or dagger.
It's 81/2 mana per cast(no cost of the echo) with 'Chain' supported which is the most cost, cast speed is 5 times per second, 81 / 2 x 5 = 202.5. So we need at least 202.5 mana regeneration per second.
If you check my character status it's 2000 mana and 215 mana regeneration per second with a lv19 'Clarity'.
If you have trouble gathering mana from gears, there are options simple helps a lot.

It's a quest reward jewel, the '3 mana regeneration per second' actually receive the bonus of total mana regeneration rate turns it to 13 in my case.

You could also find 'xx% reduced mana cost of skills' from jewel.
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And with a slight change of skill tree(3 points investment), it gives 33% increased maximum mana and 15% regeneration, that's a lot.

I played this build until around level 80 with around 4k life picking up some more life nodes around the place. I was hitting around 32k dps (buffed). Then I decided to drop Curse on hit setup and pick up and switch my ascendancy points from Assasinate to Deadly infusion to sustain Power charges. I then got Warlords mark blasphemy with vaal pact and blood rage to get both endurance and fenzy charges. I also dropped some crit nodes for the extra power charges (6 max in total). With the exact same gear im hitting 53k dps, FeelsGoodMan P.S. This can be pretty risky without good gear tho