So I recently purchased a slime spawner for a pickaxe a made, and i made a room below at lvl 20 to house it. They don't spawn though. I've seen other peoples slime spawners that work, and it's not the light level that's making them not spawn. I heard something about a slime chunk, where only slimes ...

Guys, add more RAM. It works.

same with the agility cape too I think.