[county75]

I have cement blocks in my basement, which are painted.
I started getting black spots on my paint.
I scraped the paint, but there is white paint under it which I have not been able to remove.
While scrapping, pieces of the white paint did come off which revealed small black spots in cement blocks.
I did bleach the spots and filled in the holes in the wall, I don't get water in the basement and I have a dehumidifier in one corner of the basement.
Wanting to know what would be my next step to waterproof the cement blocks.
Would a Drylock paint be OK to put over the paint to spot the black spots of returning again and possible getting a other dehumidifier?

[CyFree]

Just like the paint that is already flaking off any kind of waterproof coat will do the same.
That is because they are not able to handle the hydrostatic pressure, which results from an over saturated soil around your foundations.

When that soil is over saturated the resulting pressure pushes water against the basement walls. Since the concrete is porous, the water infiltrates it and,given enough time and pressure, it will cause the coating to peel off.

So,you will need to reapply it, over and over.

A better alternative would be simply taking every step to prevent the ground around the foundation from becoming over saturated with water in the first place.

Cleaning or installing good working gutters and extending the downspouts is the first step.
Grading the terrain as to slope away from the foundation is another thing that can be done to improve conditions in the basement.
Ultimately, improving drainage with a good drainage and sump pump system, will help keep the basement dry on the long run.

Just more one consideration: If I understood correctly, mold is growing on the paint. That might indicate the presence of latex or other organic compound on the paint. Mold needs organic matter to feed on, so it might be a good idea to scrub off all the paint and just let the basement walls bare.

If you need to spruce up the walls a bit without going through a whole basement finishing project and expenses, consider acrylic wall panels, or insulated panels for added energy efficiency.