I need help because I want to build a slime farm I have found chunks using a slime chunk finder. I have built it below level 40 at 35, It's a 16 by 16 area and I have triple checked my coordinates and seed. I have placed jack o' lanterns spaced out on it. It is in fact 3 blocks tall. I at one point left the area more than 25 blocks away and less than 40 for about 4 hours! and not a single slime has spawned. What can I do or what am I doing wrong.
If you've found this slime chink in a Swamp biome, they will spawn between layers 50-70. However, everywhere else they will spawn below layer 40, so you should be fine there. You'll need to be between 25 and 32 blocks away. Assuming you've met all of these—the slimes should spawn. Of course, I'm assuming you are playing on a difficulty other than peaceful.