I redid Oliver's tank today (he's still not in it).
last time I did one.
I'm happy with how it turned out- but was surprised at how much dark, fine mulm came up when I was gently trying to move plants and hardscape around. And it stank. I siphoned out water twice and refilled fresh, because it got so cloudy couldn't see anything. The snails seem okay with it all. But I am not putting Oliver back in for a while- and will test parameters make sure there isn't a huge ammonia spike or high nitrates.