It was an episode of Crash Course World History, which seems pretty reliable. But I googled it and couldn't find anything except a paper on him written by a girl named Alexandria. The paper did not mention the city of Alexandria.
Does anybody have any more information on this or any sources I could check out?
Here is the episode.
Crash Course is good at broad ideas, but tends to get the facts a bit mixed up. This is another case of that. Yes, Musa I did flood the gold economy with his spending, but it was in Cairo and Mecca that this was seen, not Alexandria.
Yes this is true. Since he was a Muslim, this visit was on his journey to take the Hajj. http://historyofislam.com/contents/the-classical-period/mansa-musa/ and https://smartasset.com/insights/four-people-who-singlehandedly-caused-economic-crises