If you are hiring profesional divers to place this you shouldn't have a problem. If not a few of the statements alluded to using lift bags to drop this. You need to add air as you decend not reduce. As your depth increases the air takes up less space decreasing the displacement of your lift...
Occasionally a concrete finishing crew will "powder" the surface of a slab that is setting up slow or the aggregate is not pushed down enough. They want a creamy surface for the final finish normally this is worked to the surface with a magnesium trowel then they run a steel trowel over the...
