Purify is a good counter to SoSac, not just to mitigate damage from poison decks. I recommend taking out wyrm because it's only useful when you have a surplus of
![Air :air](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/air18x18.png)
quanta. Arsenic isn't as good as pulvy or discord, graviton guard isn't as good a black hole/SoF. Everything else seems to be staple.
edit: depends what you're going against. I don't really know about PVP2, but in silver arena purify probably isn't needed. It is needed in gold if you're planning to head that direction.