Ocean Beach, San Diego, California I got some lunch in the Ocean Beach area of San Diego, then went for a walk. I sat down to stare at the Pacific Ocean for a little while, and looked over, and saw that a part of the water appeared to be red. I decided to go take a closer look. It appeared that red seaweed was what made it look that way. It was pretty cool, and slightly creepy. Talk about a crimson tide!