My friends brewery. I have to tell my friend, his plumber is not a plumber. I want to give him a correction list of what I see is wrong so far. But I don't want to suggest the sand shading because of cost, even though if it were my system I would do it. I would rather he wait for the inspector to tell him if he has to do it. Not sure if this picture will show up. There are rebar hooks epoxied in slab because they are pouring 6 more inches of concrete on top. May I get opinions of sanding the trenches. Thanks.