koro

I don't know if it's been mentioned, but you can also put faucets on multiple sides of a drain as well, so one drain can serve multiple tables/basins.

I've also found the Turtle Boss twice in the Overworld as well, both in the same Glacier biome. The first was just kind of sitting around on an ice lake, and the second was in the "secret" water-filled room in one of the Better Dungeons walker castles, the kind with the huge brick-topped structure in the middle surrounded by keep walls.

So this is happening in multiplayer too? On the SMP server I play on, I fixed up one of those "ruined" battle towers (the six-floor ones made from a mix of cobble and mossy cobble). I have a twilight portal on a chunk adjacent to the chunk the tower spawned on and a nether portal four chunks away. I also have several Secret Rooms blocks in and near the chunk the tower spawned on, but even after using the nether and twilight portals a lot, I've never had any chunk respawn on me. Edit: However, no Secret Rooms blocks happen to be in a chunk containing either a twilight or nether portal. Maybe that has something to do with it?