Because July is the middle of the summer season. Expect Seaworld to be crowded. However, it will not be as crowded as a Disney or Universal park because Seaworld is the least popular of the major theme parks in central Florida. One benefit that Seaworld offers is multiple shows. The crowds in the park die down when there are multiple shows going on because people are at the shows. If you are big into rides, then wait to ride the rides while there are shows going on and it will cut down on your wait time.
Ride Manta when Blue Horizons or the Shamu show is being performed.
Ride Wild Arctic when a Shamu show is being performed. If you wait to ride Wild Arcitc following the Shamu show, you will find yourself in a very long line.
Ride Journey to Atlantis and Kraken when a Blue Horizons show is being performed.
See Turtle Trek when a Blue Horizons show is being performed.
Another tip: Plan to get to the park at rope drop which is 9:00 and go to the 9:30 Dolphin feeding to feed the dolphins. The 9:30 feeding is the least crowded and best time of the day to go because it's the dolphins breakfast.