11:45 AM
I know it's early, but I figured I'd leave this one and come back later:
So while cleaning for a birthday party my brother is cleaning the downstairs toilet and notices that the tank fills slowly (needs a new fill valve). He takes off the lid to investigate and there's this dark glittery stuff in the toilet tank.
We're about to eat dinner so I say, lets get the wet vac after dinner and suck it out. He ended up flushing it down the drain instead while we were eating.
After the party, I receive a report that the downstairs toilet won't flush (why does this always happen during birthday parties?). I go to check it out, everything looks fine, just takes forever to fill as normal. Probably someone tried to flush it quickly.
About an hour later I go to flush the upstairs toilet and the thing catastrophically overflows. Not the normal "Uh-oh, it's almost to the top" more like a volcano.
I'm near helpless when it comes to plumbing. What the heck is going on here?