Painting concrete blocks internally

[Adam68]

I started painting these yesterday. I've noticed that when i apply with masonary roller or paint brush the paint does not go on properly.
I mean i have never painted external before just wood/metal. The blocks seem to be leaving small holes or gaps where paint does not reach until you go over it with another brush several times.
Do i need to thin paint a little as at this rate i will finish 10L paint after 2 walls.
the area is about 30m2 and it says 16m2/L so i should only use about less than third of tub.
What I'm I doing wrong? The blocks seem very dry and when i brush them they are little dusty. But i have brushed them a little as they have just been built 4 weeks ago.

 

[JohnD]

you should have applied at least one mist coat thinned with water to a milky consistency. Apply it with a brush. You may need to scrub it into the surface to fill the pores. The thinned coats will soak in and disappear. You will know you have applied enough when the wall no longer sucks your brush dry.

 

[Adam68]

you should have applied at least one mist coat thinned with water to a milky consistency. Apply it with a brush. You may need to scrub it into the surface to fill the pores. The thinned coats will soak in and disappear. You will know you have applied enough when the wall no longer sucks your brush dry.

Thanks, i knew there was someone here with the know how.
Good thing i only did half a wall.
Is the amount 1part water 7 parts paint 15-20%??