how close was the MH
to the water, if its hanging fixture with a glass cover you won't feel the heat to much unless youre within 6 inches.
i'm an electrician, and i do alot of grocery stores in some of the high end stores MH
highbays are used, and if the need to be moved and we leave them on i start to sweat cuz of the heat coming off the 400watt bulbs.
now a days all the highbays are being retro fit with 6 lamp T5HOs, the florecents keep 95% of their lumen output over their life time, while MH
drop to 50%, reason why i say my lighting choice is T5s