Which is Better MH or T5 lighting


New member
I justed upgraded in a 72 bowfront with canopy .. right now the tank has 1 96 watt pc and 3-55 watts pc with room for one more 55 watt bulb.. My question is I want to be able to keep sps and clams and I want my corals to grow( like everyone else... I like to add mh or t5.. I read a lot of post and can't make up my mind on a new light ... Whats the the pros and cons of each light type>

Give me some ideas... The canopy is a good 7 inch off the top of the tanks

Thanks in advance.. Pls respond!!
In short, MH has better penetration in water depth they can run quite hot especially 400W. T5HO are better in terms of energy efficiency and run cooler and I beleive they last a bit over a year and with high quality reflectors are better than VHO IMO.

I would suggest in youre case MH but that's just my opinion.

I would guess that 2 250W MH pendants would fit into your canopy rather easily. One end of your canopy should have a 2'' fan for outlet, and the opposite end should have a 2'' fan for inlet. You could rig up some kind of air-baffle system to maximize the amount of air making contact with your MH.

With all the talk of metal halide running hot, I rarely see posts by MH owners stating that they are having difficulty removing the heat.
I was thinking of keep some of the pc.. would the be a good idea.. kinda like a complete hood(corallife or sunpac)....
That canopy isn't very high off of your tanks, if you go with MH setup you are you lights are going to be quite close to the water which can be dangerous.

But here is my opinion.

1) Lots of light and great penetration.
2) A little cheaper to initially buy then a matching T5 setup.
3) Proven technology in reefs for a long time.
4) A large variety of bulbs, ballast, reflectors, etc...

1) Heat from the MH which means you might have to invest in a chiller of at least a good fan.
2) More electricity use. Maybe not from the ballast but to cool your tank it will cost more.
3) Shadows under your SPS due to the fact the the MH light sorts is coming from 1 point. You SPS will look great on top but the shaded areas will not have the same colors.
4) Yearly replacement costs for bulbs.
5) Tall canopy required to keep the MH bulb away from the water and allow the light to spread out.


1) Good light penetration also.
2) Ability to direct light to all parts of the tank from many directions and points; therefore no shadows and good color throughout your coral body.
3) Low heat output; there for less electricity use with cooling your tank.
4) Inexpensive to change your lighting look with the change of 1 or 2 bulbs.
5) Pretty good selection of bulbs and more coming with URI's.
6) Short canopy because the T5's are supposed to be closer to the water.

1) New technology and there are quite a few changes and testing still going on.
2) Initial startup cost high.
3) With just T5's its harder to do a sun rise and set.

I'm sure there are other things I forgot, but this is what came to mind.

I currently run a 2x MH setup with T5's for sun rise and set and actinics. I'm building a 120G system and I'm going to switch to a 8x 54w T5 setup over driven by Icecap 660 ballasts. It will be a lot of light and I hope to get very good coloring with them...

rich pretty much covered it, but all the info i see on when to change MH bulbs is 8 months. so like 2/3 of a year.

if you retrofit t5ho, and watch what and where you buy it from, you can get a good deal on t5ho, and still have proper reflectors. i got my 3x39t5ho retro everything included from aqualux for $170 delivered...

i used to run a NO actinic for dusk dawn, and now i am in the process of modifying a helios strip lite (superblue) to fit in my canopy for dusk/ dawn.

As far as bulb life of t5ho, 18-24 months is a normal lifespan when underdriven. I am on month 15 now...
horkn have you put in a newer bulb and compared that to the old bulbs and see any difference. I know IC says 18-24 months but I find it hard to believe even driving them normally. I dont doubt that it can be done but with out true numbers it is hard to say. I am in the same boat here. I dont want SPS now(later is another question) but in such shallow tank as hornk and breeders 16" for the 40g(which is what I have) and 18" for the 50g I think not much need for anything over 175w I feel unless maybe just maybe 250 20k are used. JMO.

i havent swapped any of the original bulbs yet.

i will pretty soon, I would for comparison sake if i had a spare laying around.

the problem is, i have 2 ati blues, not blue+. so, even if i get the atiblue+, it wont be the same as my existing ati bulbs. the ge day bulb i have, i like a lot, but i want a bluer look to my tank. I will see if the swap from blue to blue+ makes it blue enough with the ge 6500k day... if not, then i might go aquablue in place of the ge day..

might is the word, because i know the ge day is the highest PAR t5ho bulb around, and i do have sps and a clam in my tank.....
If they are not changing colors and going south they might be just adapting to the slow shifts but I would imagie that they would go south a little quicker with bad bulbs. I want to try MH and for the cost of T5 which with shipping $90 and for the MH bulb I want to try Iwasaki 15k $76 with out shipping I might just try the MH not sure yet. lol
Hello, dwdenny.

As a representative of A&M, please try to use better grammar on this site. I know we sometimes get in a hurry, but please try. It makes your posts much easier to read and understand. We Aggies get enough grief already without giving fuel for the fire.:D :rollface:

By the way, are you a student or a graduate?
Speckled trout this is not english class so I will stop there. BTW Class of '98 so I have been out for a while. As you know AGGIES seem to be the butt of some the jokes so you have to be like a duck and dont give a well you know the rest. I work with a bunch of Tsips and I hear it all the time.
i dont always use the best grammar ( i usually do though) and i rarely use caps for i and in sentences, not on the net at least.

but i ama grad as well or a 4 year school as well. communications at that...:lol:
Well if it is not that old it still can be good. Used is cheaper for startup reasons. Thanks for the support on the grammar thing as well. lol If I knew the person I was getting from that makes it a lot easier to buy as well. Most ballast will ast several years with no problems but it would be a plus to know how it was taken care of befroe hand. It is like buying a new car some times it is a good deal other times not so good.
Ok cool.. next question would be on my bow front how much light would you have with mh.. i dont want to have to buy a chiller just yet.. do i need two reto for either side of the tank or could i use one the middle?