No idea what Haulover Beach is like, but unless something drastically changes from when we were there a week ago, you won't want to go anywhere near the beach. The seaweed was was horrible and made the water look like disgusting. Even if you the brown water didn't bother you, the smell would probably send you running.
All that being said, just before our Pearl stay, we stayed at RM for 5 nights. The beach was pretty gross there too on our first day, but cleared up overnight and we had beautiful water the rest of our trip. Maybe things could change at Pearl that fast too.