Just because T5 is all the latest rage people are bashing metal halides. It's a crock. With halides you can have ANY thing in your tank you want. If run properly they don't heat your water that significantly. In the Winter when tank temps are cold you don't need a heater. So you don;t use the electricity, and it's a LOT, that a large heater uses. Plus, each T5 bulb costs you on average of 20 to 25 bucks a piece and have to be changed out once a year so add that up. A top of the line radium halide bulb sets you back tops 80 bucks. Use an electronic ballast with your halides and they are pretty energy efficent. I use two 250 watters and 1 400 watt on my 220. The 400 runs 10 am to 8pm and the two 250's from 1pm to 6 pm. They use only two kilowatts per day (I used a meter) which costs me a total of 35 cents a day to run my lighting. I don't have to question whether I can keep ANY corals or clams, I know I can with this lighting. I think people are simply taken in by sleek looking T5 fixtures. Want to pay for looks or keep your corals healthy? I'm a little tired of all this rage over T5's and metal halide bashing.
Woah Woah Woah, calm down, buddy. No one is saying that MH sucks and is outdated. Truth is, if they weren't so darn expensive, more (if not most) people would get them, including myself. A good T5 system runs about $400 whereas a MH costs $700+.
Most people (from reading this and other forums) change their MH bulbs each year. Let's say you change 6 T5 bulbs every 6 months, you'll spend $240/yr... MH would be $160/yr for 2 MH bulbs(yea, cheaper), but when you add 2 T5 atinics (to be changed out every 6 months) in the equation you come up with the same price in bulb replacement. An even better MH system will have 4 T5s, therefore making it more expensive when it come to bulb replacement.
As for energy consumption, you really don't have an argument to say that MH is more efficient than T5s. I know you didn't say that, but it sounded as if you were trying to push it.
Personally, I would rather not worry about what I can and cannot keep in my tank, but that's one of the trade offs offered when choosing T5 or MH.
Finally, MH do heat the water and the room they reside; I really don't think chillers would be so popular if this weren't the case. A buddy of mine had a 100 gallon with a Hamilton MH 2x250 system and he had to get a chiller, even with it ceiling mounted about 16-20" from the surface (the protective plastic on the warped as well because of the heat).
So am I saying MH is dinosauric? No. Are T5s the better buy for reef enthusiasts who don't have deep pockets or can't afford to drop $700 in 1 payment? Yes.
