I currently have 2-20,000K DE 175 watt metal halide bubs running on my fish tank. I've had them for a while now so I definitely think it's time to change them. I don't really know if I should keep the rating the same. I have a 75 gallon reef tank with lots of caves and a couple fish but mainly going to be inverts and corals. Would like some suggestions and also where I can find 175 watt DE bulbs since I've mostly seen mogul base 175 watt bulbs only. Thank you