Poop?! in the Pool

So we were at the hotel pool and the kids were swimming. Everyone was content. Until I noticed a small group of teenagers leaving the pool area for what they thought was poop at the bottom of the pool. I looked at the area (the pool is made entirely of stainless steel), and saw a rust spot in the area they were talking about, so I thought it was no big deal. Maria and Sam had fled to the hot tub with the other kids, and I knew Ben was on his way down to swim, so I thought I would ask him to check it out when he got there, since I did not have my suit on the investigate further.

After I told Ben about the debate and he got in the pool, he agreed the spot was rust. So he and Maria and Sam swam for a little bit, then Ben noticed some stuff in the drain ledge, looked at me, and said "THIS could very well be poop."

So I went to the front desk to report it. Nothing brings the manager as quickly as the phrase "What looks like human feces in the pool." When he got there, he told Ben he thought it looked like mud. "See, there's rocks in it." Ben mentioned to me later that the manager was young enough that he probably didn't have kids, and that we've seen a lot more poop than he has. Then again, maybe they learn that in hotel manager school - "Always insist its mud, no matter what." Regardless, they closed the pool for a time and we left to go have dinner.

Now, 3 hours later, the pool is back open and Ben took the kids back down there. I just have this bad feeling that whenever I look in there, I'm going to see poop whether its there or not. It reminds me of Caddy Day at the Pool in the movie Caddyshack.