Club soda is slightly different from seltzer water. Club soda has mineral-like ingredients added to enhance the flavor. Usually potassium bicarbonate and/or potassium sulfate. It's not much of a difference in taste, IMHO.
If you are looking for club soda you can just add a little baking soda.
When I make seltzer I run at 30 PSI for about a week. It really depends on how cold it is, how long you leave it on the gas, and how carbonated you like it. Start at 30 for 3 or 4 days and go from there.
Primary: Ginger Beer
Kegged: UpstateMike's Caramel Apple Cider, Strawberry Graff
Bottled: Edwort's Apfelwein, Brandon O's Graff, More Graff, Spiced Graff, Ginger Beer
Up Next: Graham's English Cider