Is that not a lamp stand behind the tank? Use it. That's how I ran my CHEs when I did. The lamp stand makes things much safer and easier.
I also hope you have a tstat or dimmer. I only used 100w CHEs that were cut back on power. That was in my apartment that I kept 68 degrees. I can't imagine you needing a 150..... Or having it at full power on top of the cage like that.