I agree. Mine used to spawn like clockwork as well until I lost the female. The one action I noticed most prominently was the cleaning of an area of rock, usually by the male. They vigorously pick at it for a few days before laying the eggs there. My clowns always laid the eggs at night it seemed and after about a week they seemed to always hatch at night. I assume they got eaten because I never tried to rear them to adults.
At Macna in Houston two years ago, I saw a clownfish breeding presentation where the guy shined a small bright light at the water surface. Right near the light was a small suction device I believe or a container. The fry are instinctively drawn to the light, he said, so when they are hatched they would swim to the top of the water surface and end up in this container in the morning. Said it worked for him everytime. Wish I could remember his name...