I'm close to finishing my ice farm. Ice is generated on top of the player and pushed down by flying machines, the player is below in a waterstream and harvests using an auto clicker.
The collection area below consists of rows of bottom slabs (hoppers below them to pick up items) separating the waterstreams and ice below the water. The only spaces without water are covered by signs (see screenshot). However, I still see zombies, creepers and skeletons spawning. I replaced the ice with glass, and still see zombies and creepers.
I thought that mobs can't spawn on slabs and on transparent blocks. Clearly I was wrong. What's the mistake, and how to spawnproof this area?
I guess I could use gazillions of jack-o-lanterns below the collection area (low enough such that the ice doesn't melt), but are there blocks I could use (that still allow the waterstreams to work) to prevent mob spawns?
I think they are spawning at the iceblocks. You got bottom slabs everywhere on your screenshots, nothing can spawn on top of those.
What about your redstone device? Did you spawnproof that as well?
Yes, the mobs spawn on the ice. More precisely, they seem to spawn on the 1x1 blue packed ice patches with signs in the block above (breaks in waterstream). Unfortunately I need these ice patches for water transport. Any idea how to spawnproof this?
Update: Seems mobs can spawn on packed ice but not on normal ice. I guess I'll replace that packed ice with normal ice. It should still be slippery enough to make the water transport work.
Redstone is not a problem. I use several flying machines but very little redstone, and this is away from the farm and lighted.