Metal halide light source is next to sunlight. We actually can get suntan from it. So be careful with the UV rays especially when there are ppl around in the house.
Leaf burn is immediate if the plant get burned. You can see totally bleached or brown patches on the leaves within a day or two. If not , then the plant is safe within its' tolerance range.
David, I don't want to unable to recognize you after a year or two
