We call them voids . Sounds a little coolermore pretentious . Tapping helps . Mix design is also relevant . If your professional you ' ll have a vibration system but that ' s a bit much for a one time DIY project . I like to keep some extra dry mix for filling . If you ' re pigmenting use powder pigment and mix it dry first without any coarse aggregate . Then put some aside . Use acrylic admixture in place of water for the fill <| sep |> One Plus released their Marshmallow update for the OP 2 in June 2016 , and HTC released their Marshmallow update for the M 8 in January 2016 , so not that surprising . <| sep |> 18 C provided the platform to bring these students to national attention for things they didn ' t do . <| sep |> Heh . Thanks sis . I try my best .