I use 1/2" hose to feed the pump from the tank, with this check valve on the line:
https://www.kleen-ritecorp.com/p-3259-kleen-rite-1-2-f-x-f-1-2-l-brass.aspx
It creates some restriction, not enough to cause any issues, and the way they go together there's no way for the spring or seal to come...