Caustic Arrow DoT Build?

I was thinking about building around Caustic Arrow and stacking "Chaos Damage" nodes and "Damage over Time" nodes. Basically a fire and forget build. I figured Assassin would be best since it has Noxious Strike and the "Damage over Time" nodes would effect the bleed and poison.

These are the gems I was thinking about, let me know if there are better options.

Caustic Arrow
Pierce
Greater Multiple Projectiles
Increased AoE
Rapid Decay
Poison

Passive skill tree down to just the basics.

https://www.pathofexile.com/fullscreen-passive-skill-tree/AAAABAYBAQW1BnAHmQ5ID6sQexEPES8TbRQJFLAWvxewG8gjNiSLJogqWysKNj1DNkcGSRNKi0wtTI5On1IpUq9S7FMQVeBYWlnwXEBn_GqMbAhtbHWedoJ59np_gh6EoofLiEKJ4I_6kx-i2aebrJitSrDYtMW00bVItzC7Tb46wQDBxcLswzrIDMgUzxXP3dDQ2xrb591f44TmWOd06FrrY-wY8Yr1S_Vv99c=

Passive skill tree if I put all the points into it.

https://www.pathofexile.com/fullscreen-passive-skill-tree/AAAABAYBAQW1BnAHHgeZCPQOSA-rEHsRDxEvEVATbRQJFLAV7Ra_F7AbJRvIHU8d2SM2JIsmiCaVKlsrCi0fNbk2PTpYOw1DNkNURwZJE0lRSotLCkuuTC1MjkyzTp9SKVKvUuxTEFS9VUtVxlXgWFpZ8FxAYQZh4mKsZ_xqQ2qMbIxtGW1sdZ51_XaCefZ6f4Ieg9uEb4SihMWHy4hCieCNv4_6kx-VLpaLm7WdqqLZpyunm6k0rJitSrDYtMW00bVItzC32btNvOq-OsBUwQDBxcLswzrIDMgUzxXP3dAf0NDUQtW52VvbGtvn3V_jhOZY53ToWujW6QLrY-wY7-vw1fGK9HH1S_Vv99c=

Gems:
GMP is not needed if you take increased aoe. Poison is also a very bad choice.
Take void manipulation and empower instead. The latter is a good choice as the standard weapon for caustic arrow is a bow that has +1 level to socketed gems and +2 level to socketed bow gems.

Corruption ain't worth taking as the point investment to get there is too high. It is better to go for projectile nodes in the ranger and duelist area.

Have a look at Grocery's Caustic Arrow Trickster Shadow for a decent CA tree. You don't have to take the scion life wheel and still have 170% increased life.

Would the "Spell Damage" nodes work? The idea is for the cloud to do the killing.

This is what I came up with after taking your advice.

https://www.pathofexile.com/fullscreen-passive-skill-tree/AAAABAYBAQDuAdEFtQZwB5kIiQ5ID6sRLxNtFAkV7Ra_F7AZhhmKGo0byCCcIzYkiyaIJpUqTSpbKwos6TBxNZI2PTfUOkI64T8nQzZFlkcGSRNKi0rISwpLeEyOTeNOn1FHUUxS7FMQVL1VS1nwWyZcQF1oX7BhBmHiYqxqjGyMbWxuqnWedf12gnn2en99W3_7hG-EooTFhrOHy4ngjb-P-pMflQWWi5cGmvGbtZ2qoSKiQKLZplenm6k0rEev67DYtMW00bVItfK3MLfZwuzDOsSiyAzIFMpKyqnPFc_d0NDUI9RC1bnYvdvn3ajigOOE5ljndOha6NbrLOtj7T_xivJF9Pj1b_4K_o8=

This is another.

https://www.pathofexile.com/fullscreen-passive-skill-tree/AAAABAYBAQDuAdEFtQZwB5kOSA-rES8TbRQJFe0WvxewGYYZihqNG8ggnCM2JIsmiCaVKk0qWysKLOkwcTWSNj06QjrhPydDNkWWRwZJE0qLSshLCkt4TI5N406fUUxS7FMQVL1VS1nwWlJbJlxAX7BhBmHiYqxqjGyMbWxuqnWedf12gnn2en97w31bf_uCXoLkhG-EooTFhrOHy4ngiq-Nv4_6kBGTH5aLlwabXZu1naqhIqJAotmmV6ebqJqpNKxHr-uw2LTFtNG1SLXytzC32cLswzrEosgMyBTKSs8Vz93Q0NQj1ELVudi92-fdqOKA44TmWOd06Fro1uss62PxivJF9Pj1b_4K_o8=

I feel like the one arrow wouldn't be enough. If I don't take Empower would Increased Duration be a good choice?

This is probably my favorite one.

https://www.pathofexile.com/fullscreen-passive-skill-tree/AAAABAYBAQDuAdEFtQeZDkgPqxEvE20UCRUgFe0WvxewGYYZihm0Go0byCCcIzYkiyaIJpUqTSpbKwos6S2DMHE1kjY9OkI64T8nQzZFlkcGSRNKi0rISwpLeEyOTeNRTFLsUxBUvVVLWfBbJlxAX7BhBmHiaoxtbG6qdZ51y3X9doJ59nvDfVt_-4JeguSEb4SihMWGs4fLieCKr41-jb-P-pARkx-Wi5cGm7WhIqJAotmmV6ebqTSsR6_rsNi0xbTRtUi18rcwt7a32b6nwuzDOsSiyAzIFMpKzZjPFc_d0NDUI9RC1bnYvdvn3ajigOOE5ljndOha6NbqYuss62PxivJF9Pj1b_4K_o8=

Spell damage doesn't work with caustic arrow as it isn't a spell.

Poison modifiers like Fatal Toxins also don't apply as the cloud is chaos damage over time, but not poison damage. (Poison is a subset of chaos damage: Every poison damage is chaos damage, but not every chaos damage is poison damage).

Increasing physical damage with Master of Force, Will of Blades or Deadly Draw only affects the damage of the arrow (which is negligible) but not the damage of the caustic cloud that is released by the arrow.

Projectile damage nodes like Ballistic Mastery or Sniper do apply to the cloud though.

The caustic clouds don't stack, meaning that no matter how many arrows you fire in an area, only one of the clouds will do damage to the monsters in that area.
The playstyle with caustic arrow is firing one arrow and move on while the cloud kills the monsters. If some survive you fire another arrow after a few seconds. Increased duration in your gem setup would just be a wasted slot.

Your basic gear and gem setup for CA is pretty much set in stone at the current state of the game:
You play CA you need a +2/+1 bow in endgame and use a drillneck quiver as it can give up to 100% increased projectile damage that applies to the caustic cloud


CA - pierce (because of more multi + drillneck bonus) - void manipulation - rapid decay - empower is given. Scaling the damage with +2/+1 level from the bow and +3 from a level 3 empower (empower gets +1 from the bow which then gives an additional +1 to CA) gives you a level 26 CA (27 if using a level 4 empower but that gem is expensive). Those extra levels double your base damage.

For 6th slot you can switch between increased aoe (increases clear speed if your damage is high enough in endgame as it covers more space) and concentrated effect (huge damage boost). Use the latter if you need the extra damage (switch to it before boss fights).

Here is a modified version of Grocery's skill tree that i would use in softcore:
CA trickster level 90

You want the frenzy charges as they give 4% more (multiplier!) damage per charge that applies to the cloud.
You could pick Phase Acrobatics instead of some projectile damage nodes at the ranger start.


Auras: Clarity, Grace
Curse: Vulnerability
Apply the curse with Frenzy-GMP-curse on hit-vulnerability. That also gives you frenzy charges.
Use spell totem - wither

BTW Level with another bow skill (Tornado shot, blast rain or lightning arrow for example) with "normal" bows that focus on physical damage.
for example. They aren't expensive and good leveling bows until you get your +2/+1 and can switch to caustic arrow (CA sucks for leveling).

Oh and you usually craft the +2+1 yourself after having aquired a 6link bow. That's the expensive part of the build: How to craft a +3 bow

After looking at that Passive Tree I came up with this one. I had to get out of some of the "Chaos Damage" nodes in favor of more "Damage over Time" and "Projectile Damage" nodes. I read on the wiki that "Projectile Damage" increases both the hit damage and the cloud damage so I focused on those instead. I think this one gives me enough life and general survivability compared to my last build.

http://poeplanner.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