That's the thing with dry rock, people assume that it's ready to go right in, but that's almost never the case. Treat all dry rock as if it came from an old system and has been dried. You need to clean and cook the rock. Bleach and a quick acid wash will do the trick 99% of the time. After it's been cleaned, you need to seed it and cook/cure the rock, this may take a long time, up to a year before it's actually seeded with the proper bacteria/biome.
