May be a silly question.....what's a prop tank
I have a sump, with a fuge built in.....I've had the power go out and everything works great! My tank is not drilled, I have an overflow converter hanging off the back. My skimmer is also in the sump. It's a 130gal tank with a 25gal sump, and it all runs off one pump. The converter is hooked up up a powerhead so it automatically primes itself when the power comes back on.
I'm still fairly new at systems with sumps....but your setup looks a little complicated to me.
Luckily I had a lot of help with mine.