I've painted a lot of cement block. Int/Ext and a garage too. I've never primed. Used Coronado's Aqua Stop-It. Due to the nature of where the block is located in *the envelope* of the structure, I felt it needed to be sealed, not just painted.

Aqua Stop-It can be tinted to a light color only - and even at that, the counter staff might push back and resist tinting it. But it can be done they just won't make you any promises.

Others may have a favorite brew for block. This is just one idea.

Here is a link that might be useful: Aqua-Stop-it

Thank you for the quick reply.....now if we can go 3 days without rain.....lately its about 3 hours w/o rain.
It took me an hour to find the paint and another half hour for the Lowes people to tint, it took 3 of them to figure it out...probably min wagers.....saving money can be expensive...