I found two pumps, one puts out 1.5 - 4psi and the other puts out 3-4psi. Why would the psi vary, or can they be set? They are solid state pumps, Facet brand.
http://www.ebay.com/itm/300779321736...84.m1438.l2649
http://www.napaonline.com/Catalog/Ca...051_0362409877