I have a heigth restriction. If you look at my build thread you will see in the closet that the ceiling is at a angle because the closet is under my staircase. With that said the lights will be a maximum of 8-10" of the water. MH fixtures take up more space so it would be more like 8" off the water which is to close. I may be able to get away with the 150w If I can keep it cool enough in the closet.