Null vs Greater Null potions
 

Looked at wiki on this and I can't tell the difference. What's going on here?

The link on the individual page has them with the same buffs, but the alchemy page lists their real buffs:

Greater Null Potion 31 39 35 37 349 +25dex +25MR -15agi

Null Potion 12 16 14 17 136 +15DEX +15MR -8AGI

https://wiki.project1999.com/Skill_Alchemy

Perfect thank you!

So just FYI they do in fact have the same buff ... but it's a buff which has level-based effects. Each item "casts" at a different level, so that's why many different potions share the same effect name, but have different effects.