If Western Pump don't have it then I have no idea.
But ... Isn't that Lanthanum basically, and isn't Lanthanum the stuff used for FozDown?
http://www.oceanfreshaquarium.com/foz-down/ ... maybe that is easier to get in smaller quantities.
Used to be that Red Coral sold it locally. With them gone I'm not sure if anyone else carries it locally. Might be worth a few calls to stores..