I noticed that they switched out the pyro effects for Spark.
The first 2 weeks they were running with fireworks that were launched on the stage and off the roof along with 5 stations on the stage that were doing fireballs.
Today they had no fireworks and had 3 directional flamethrowers on the roof instead along with the 5 fireball stations on the stage.
I assume the flamethrowers are cheaper than shooting off an extra set of fireworks every night.
Either was pretty nice looking and they use the flamethrowers more than they did the fireworks, so it's not necessarily a downgrade.
Edit: I just read in the Summer Nights thread that they had a fire due to fireworks bouncing off the roof onto the stage. I guess they replaced the fireworks with the flamethrowers to avoid that issue in future.