My water table is 4" deep and I haven't built in my permanent support bars yet; I keep the water level about even with the surface of the steel I am cutting, so the real water level is about 3.5". I use a Poweremax 600 with finecut consumables, so the air pressure at the plate is about 70 psi. I don't have any automatic way of controlling the water level so it is sometimes slightly below or above my sheet steel (I fill it with a hose on cut days). My setup doesn't seem to splash or spray water and it seems to control the plasma dust, smoke and fumes. Some ventilation is still needed to get rid of a small amount of smoke or fumes coming off the upper surface of the steel. Also, note that I am cutting steel. I have been told that cutting aluminum above water can create a hazard because the aluminum plasma combines with the orygen in the water and releases hydrogen which is explosive (I don't cut aluminum and don't know if this advice is true.) I did have a rusting problem, but solved it by putting washing soda in the water. Also, when you have completed a cut, make sure the nozzle is raised above the water level.