First Sump - Need Help

[raulfd4]

I have started to build my first sump. See attached image of the plans.

Main tank is 65 gallons with a drilled overflow and return. Sump is a 20 gallon long.

So far, I have only siliconed the baffles into the sump. But, I have all the other plumbing and stuff ready to go.

Questions:

1) Is putting a ball valve on the tube overflowing into the sump smart/necessary? I want to add it in case I want to stop the flow in an emergency.

2) Is the check valve on the return tube smart/necessary? I want to make sure that water can only flow one direction on that line, obviously.

I will have more questions (and photographs) later - but for now, let's start with those.