Welcome to Reef2Reef!!! You have a few things to consider - the spread of the light (at what height is the light covering everything uniformly - unless you intentionally want some low light areas), what type of corals that you are keeping and their light needs, and what looks good to you. If you can get a hold of a PAR meter that would be helpful. Good luck!
What is the normal height ppl use for a 150 watt light say 165 vispectra even hope to get a more helpful answer other then the obvious thanksHi I have a red sea 130 max what would the right height to set the lights, above the water? The light is a hyper reef 150, I'm currently at 17 inches from top of water should It be lowered?
I would think if they are growing perfectly fine the way it is I wouldn't wanna mess with it. If you think the hammers will extend more because you move the light down a bit then go for it. Don't move it down a ton at a time, move it down an inch or so and see the difference