too much light?

I would not exceed 600w at less than 27". Your light manufacture may have suggested height settings for veg and flower. In my experience max 400w thru veg then up to 500ish during flower. There are other factors such as air movement & temp. To much heat stress from lamps can cause burnt leaf tips, burnt pistols and fox tailing. Less is more if it means a happier plant. Stay Frosty Friend!