Toxic Rain Pathfinder - Malevolence vs [Skitterbots & Hypothermia]

I'm currently playing as a Toxic Rain Pathfinder via SSF. I have a bow with all phy/fire/cold/lighting damages. Due to the lacking of mana, I have the following 2 options:

Use Malevolence: Deal 20% more Damage over Time, and have 19% increased Skill Effect Duration.

Use Skitterbots & Hypothermia: Guaranteed Chill and Shock effect, plus 29% more Damage with Hits and Ailments against Chilled Enemies, +20% chance to Freeze Enemies which are Chilled, and deal 39% more Cold Damage Over Time.

If it would be great if I can run them at the same time, but I don't have Enlighten Support for now so I can only choose 1 of them. Which one is better? Thanks in advance!

You are misreading Hypothermia. The bonus only applies to linked skills, and Skitterbots deal 0 damage by default. Your mana reservation will still go up tough.

Skitterbots + Bonechill is the standard combo, but that is only relevant to cold builds. A little bonus cold damage on your bow doesn't warrant the cost of Bonechill. Skitterbots on their own is still a good choice.