You need to have the sizing figured out and be sure there is no way a siphon can form so that you will never have an overflow from your sump onto the floor.
i had a straight drain pipe from the bottom of the tank with a stand off pipe and didnt allow for power outages..that was my first split system and it just wasnt plumbed right
A good check valve is always a good investment. I put one on my frag tank return line and it works great. Never have to worry about a siphon. I've had issues in the past with algae growing over the anti-siphon hole and a little overflow.....Wish I put them on my display.