5th Gen Fifth Gen Quick Questions

[Pendraflare]

Uh, okay, so i'm playing Black 2 right now, and the other day I was in the sewers looking for the Black Sludge. According to Bulbapedia, it says that it's west of a Max Repel that's near that one Janitor who you battle early on, and it can only be accessed in the spring or summer. But i've looked in so many different areas, and I haven't found it yet. I'm in the sewers right now, as well (as i'm typing this) and still haven't found it. I even checked Marriland's walkthrough, and it made no mention of the Black Sludge in the Surf section. Am I going crazy here, or is Bulbapedia erroneous on that claim?

EDIT: Nevermind, just found the Black Sludge, I followed the steps in Marriland's video given on the walkthrough to locate it. Thanks!