Just got an email that the $1 per gallon sale is going again. I did notice a change this time, no 20L offered in the sale.
http://petco.shoplocal.com/petco/default.aspx?action=detail&storeid=2602770&rapid=0&listingid=-2041162519&offerid=
http://petco.shoplocal.com/petco/default.aspx?action=detail&storeid=2602770&rapid=0&listingid=-2041162519&offerid=