What I use to color Ytong is pigment powder, available in most specialised paint- & hobby shops.
Just mix the powder with some water and paint it on the Ytong, the water is instantly absorbed and the pigment remains
Like this: http://www.earthpigments.com (first hit on google)
Hi new to this quick question can I use a aerated block instead of ytong or siporex or thermalite blocks or they all the same