T5 or Metal Halide

good advice everyone.i agree with everything said.another bonus with t5's is less heat.a con is that corals have to adjust cause most likely they were under mh or vho lamps at the fish store.also,at 18 inches the light is still very bright so its not as simple as moving low light loving corals like mushrooms to the bottom.i've had to move some under the shade of other corals or wait a long time for them to adjust to the higher light before they adjust and expand.i use 2 54watt 11,000k and 2 actinic geisman bulbs over my 55 gallon soft coral tank with no fans needed.its like the tank itself becomes a bulb.my last set of bulbs were uv brand and lasted 11 months but i think it was cause the ballast was to close and got them hot.i fixed that.i'm happy with my t5's but if i had a big tank i would not have anything against mh lights either

 

I beg to differ that one....it matters how many hours a day you are burning your MH's as to when they need replaced. I burn my Actinics 16 hrs a day and only burn MH's for 7 hrs and have fantastic results. I bought a Spectrometer so I could keep an eye on the bulbs and they are going on 13 months now and are doing fine on my checks.

Everyone has their own opinion on lighting, you just need to make the right one and hope that you don't have to upgrade later on because you made the wrong choice.

 

halides lose about 30 percent of their efficiency after i believe 10 months or so. but after that they lose like a percent a month or some ridiculesly low percentage. But the spectrum shifts and algal growth MAY follow. T5s are great as i hear it. Energy effiecent and all, but i have apreference to Halides. Just love the ripple.......

 

Is this something you read or personal experience???

If the latter then how many hours a day were you burning the lights and what type of ballast were you using?

 

its not me, its something i read here before. Cant remember who posted it, but they said halides would work for a long time, its only the spectrum that shifts and the amount of light emitted decreases to about 70% of when brand new. And im pretty sure the months was based off an 8 hour a day burn time.
Still no excuse to not replace your bulbs, but just shows that Halides dont need to be constantly replaced.

 

Once you learn your tank and use the right equipment to do the test you will find out how long the lights will last. I will post in my build thread when I see the spectrum shift and I change my bulbs. I already have bought the new one but they are just sitting in the boxes waiting.

 

Same, my bulbs just hit their 8 month mark and look as good as when new

 

Most manufacturers reccommend replacing them long before 13 months. Im not sure what the burn time is based on though. A lot of it has to do with the ballasts you are using too. A crappy ballast will cause the spectrum to shift as soon as you put a new bulb in. Ive seen that happen first hand.

Otty, if your bulbs are 13 months old, you're going to shock the crap out of your corals when you replace them, reguardless of what your spectrometer is saying.

 

My bulbs are around 7 months old (radium 14,000K) and already starting to have a greenish yellow tint on start up, but I run them 9 hrs a day.

 

i'm a recently converted true m.h. believer, i'm not saying t5 is bad but just as an example... my 1 150 watt m.h. shines through the 120 past the 1/4''{give or take} of sand and into the sump,i have algae growing in the sump with no other light source, not to mention the disco effect rules! try doing that with t5