The set up looks fine but my only constern is the sizes of your tubes. In the picture your drain looks about the same size as your feed line. Just wondering what the I.D. was?
The only thing I see is that maybe have your union below the valve on lower return to spray bar? The valve on the drain would only be needed for a'Herbie' style with an emergency drain along side. Is this a Durso style? Also need to be careful with vinyl hose on bends as they have a tendency to kink.Cheers, Todd
Never ever rely on a check valve! They can and will fail and usually at the worst possible moment. If your sump is not large enough to contain every gallon of water above the check valve then eliminate that return. It will get you into trouble almost guaranteed.