One of the most common series of centrifugal pumps would have to be the C-Series pumps. Many distributors carry this pump, making it virtually universal. This pump has been an industry standard for many years.
Koss Industrial has the C series pumps available to purchase online. For sizing your pump correctly, give John Koss at Koss Industrial (1-800-844-6261), Inc. a call to ensure your getting exactly what you need at an everyday affordable price.