1kOaks is a bit far, unless it's a really good one. I live in El Cajon, but am working in Valencia for several weeks... I need some substitute tanks to stare at occasionally while I'm away from my own
Valencia Pet In Valencia has Salt Water. Not alot but and usually a bit high priced. The closest decent place I usually go to unless I am in a hurry is Rainbow Pet. Aquarium Works is also not too far. There aren't alot of choices for people living in the Santa Clarita Valley.
There is also a placed called advanced aquatics on san fernando road. I go there for a lot of my stuff.. Not a giant selection, but they usually know their stuff.