You only have to put a glass shiled on the lights if you use the HQI double ended bulbs. The single ended bulbs are wrapped in a glass tube so there is not a need for a UV
shield, but many people still put glass between the bulb and water to prevent any splash from causing the bulb to explode. I currently run a single 250w bulb with no shield, but have just order a 3x175 HQI with glass shielding. Either way, MH
is the only way to go, not only does it look awesome, light sensitive creatures love. Just be sure to acclimate your inhabitants to the new light with some layers of screen so that you do not shock them with a new "sun".