To preface, by no means do I think this is the actual fastest time for this particular route. That being said, it is a rather popular loop among ultra-runners in the area, so I wanted to post my slow time with the hope of seeing what some faster runners can do.
The loop starts at the Elena Gallegos trailhead in the Sandia Foothills, then heads north along Trail 365 to the Sandia Tramway station. From there, a small trail links up to the iconic La Luz Trail. This trail goes to the crest or, when doing the Watermelon Loop, follows a path to the Ski Lodge/Tram station. The South Crest trail is picked up at the ski area and followed to the top of the Pino Trail. The Pino Trail is then followed back to the Elena Gallegos parking lot. This clockwise direction is the standard direction.
The route is right at 21 miles, with ~4700' of vert. My time was 5:27:00.