I have a 75 gallon SPS tank. With a sunpod 2X250 48" metal hallide fixture. I originally had the light sitting directly on the tank (with the provided legs). I have noticed that no matter how deep I put my coral I keep bleaching them. I have even bleached some of my rock. My water specs are perfect, so I assumed that it was a light "overkill". I just mounted the light 6-7 inches over the tank using a hanging ceiling mount. Is this a good height? what height to you recommend?