I just finished tiling a bath and entry hall and today I sealed both with two coats of sealer. When the grout is wet, the color matches the sample chip. But then the sealer dries and the color becomes much lighter...not the look I was going for. Do I have to continue to apply sealer till it won't absorb any more and the color changes? The bottle said two coats should do it but the grout still soaks up the sealer.