Thoughts on T5 versus metal halide:

[Julie]

Metal halide replicates the natural sunlight, a definite plus. 
However it's hot, and costly on bulbs and hydro.

T5 is flourescent, doesn't penetrate to the greatest depths according to some(however I believe there is a thread in reefcentral stating it does)
It's cost efficient.

I'm looking for opinions to convince me to purchase metal halide over T5. 
I honestly prefer the majority of lps over sps.  There's a couple of sps I like but otherwise....
tx

[BigDaddy]

I would say alot of your decision making will be based on the depth of your tank.

[Julie]

19" or so.

[FishPassion]

Also you have to kinda keep in mind what you are planning on keeping in future, I went MH because that way I was sure of having enough light to keep whatever I wanted. I didnt want to switch again in the future re: pc to?  hence some of my pc lighting will be sold unless I decide something silly ex: planted tank. Im really glad my wife never goes to this site and reads my thoughts...

[Seanc]

how big is the tank going to be?

I realy like how the MH make the water shimmer, its realy cool looking.

[Julie]

55

[luker78]

As long as you have enough wattage, your more than fine for almost anything in that tank.  As for the cost difference, it's huge.  The operating cost per month is much less with T5's.  I don't know the cost difference in bulb replacement though.  I don't think I would keep clams under t5's and some sps may not like it but other than you should be fine. 

[Seanc]

do you already have the tank?
If you don't then i strongly recomend you upgrade to a 75. It is only $10-20 more for it,  and it is alot wider, wich will make so much easyer to aquascape. thats just a sujestion.

i like my MH's and if you hace the balasts separate they don't produce as much heat.

[NjOyRiD]

i use a t5 on my 65g, i really like it!
i only have anubias in the tank tho

[gvv]

I realy like how the MH make the water shimmer, its realy cool looking.

Same here.
Also agree with Seanc, if you are planning to go with 55G, it is better right now go with 75G, if there is no place limitation.

As for T5... Saw some setups that were using only T5 and mixed (I have mixed myself). You may even have clams with T5 if they will be placed not on the substarte, but in the middle. But what type of lamps are you planning to have? If you are planning to use cheap ARC bulbs, I'm not sure the intensity will satisfactory, while other lamps are pretty expensive - about $20-$25 ea.

From other side, I'm not sure MH alone is a good choice... I prefer to have both, than you may simulate dawn/dusk.
Does it help?

Regards

[gvv]

But I forgot to mention:
I'm not sure one MH bulb will be enough for the 75G tank. Even for 55G. I have 1 MH 400W bulb on 90G and I'd prefer to switch to 2x250W, as there are a lot of shadow spots...

This is not a case for T5 setup, when everything is covered.

[Julie]

Hi, thanks for the input.

It's my oldest tank the 55,  I am moving my discus into the 90 and moving the 20 reef into the 55.
I made this decision because the 90 is 28" deep, which is too deep for my liking coral wise.......

I agree the shimmer is awesome with the halide.  I see a cooltouch at ac I may invest in.

Thanks

[BigDaddy]

You want one MH bulb for every 2 square feet.  So regardless of your choice between the 55 or 75, you want to get two bulbs over the tank.

[Julie]

Which is better the 175 or 250?

[BigDaddy]

Depends on what you want to grow and how deep the tank is

[Julie]

It's 18" and I'm not sure what I want to grow.  I think I prefer LPS, maybe a couple sps - like a plate.

[BigDaddy]

If sps are on the menu, then 175W MH should not be

[Julie]

tx bd, was on richmond road last night and saw the hydroponics shop and thought of ya....
Julie

[babblefish1960]

The hydroponics store on Richmond by MEC is a good place to get things, and they are accustomed to salties, you'll note they have some stuff there for fish, and they have a very friendly rottweiler, most of the staff and the owners have had fish at one time or another, so they won't look at you like your an alien as they have been asked about everything, including grow-ops like dpatte has. 

The largest difference in my little opinion and experience has got to be that the electronic ballast is much cooler for nearly the same light, however, the MH below 175 is almost pointless and unfortunately, MH's are very hot, so consideration must be given to cooling the surface too.

Having said that, the MH gives a much more realistic light that can never be produced with flourescents, but at that depth, you could almost use them interchangeably. And for reasons I do not fully have researched, MH still requires a little flourescent assist to meet everythings needs in a reef.

This way you get full coverage, the delicate sunny shimmer, and as has been pointed out, the ability to do the dawn/dusk lighting that is not possible with MH alone. Don't forget about actinics too, as you'll want something for overnight as well.

[BigDaddy]

I remember reading an analysis somewhere that showed that a double-ended 150W bulb did just as much as a 175W does.

So, if you go with a shallow tank, go with 150DE bulbs and save a bit on your hydro costs