basement paint?
 

is their a sealer/primer to cover basement walls that already have multiple coats of paint, to better seal them??

UGL Drylok, is the most popular brand here.

http://www.ugl.com/images/DRYLOK/dryloknewgrp2003.jpg

http://www.ugl.com/DRYLOKframes02.html

It can be rolled on or brushed, Be sure to well ventilate the area you intend to paint before you start. Outdoor temperatures start to become a major consideration this time of year, The walls need to be 50degrees or more for paint to cure completely. Check the manufacturers label for more details. Different products will vary in dry times and teperature requirements.

I have used UGL products over old paint with great results. It can be bought tinted, I don't remember if it can be custom mixed, but I would use this as a base coat and put the finish color over this anyway.

Good luck with it,
Tom

Iv used the berh plus 10 and it works great for me