You have a coincident surface with the liquid
surface and the "fog" bottom...
difference { // some fog over the liquid
sphere { 0.0, 0.98 }
box {-<1.2,0.05,1.2>, <1.2,1.2,1.2>}
box {-<1.2,0.149,1.2>, <1.2,-1.2,1.2>} // <-- changed
pigment{ color rgbt 0.9 }
interior_texture { pigment { color rgbt <0,0.1,0,0.9> } }
}