metal halide

[the_one_and_only]

First, I'd like to thank everyone for all the help that ehy have provided so far.

I am not on Lighting - I have a 55 gal and want to get some corals. I was told that I should probably get one metal halide with a 450 Watt bulb. Is that too much? Would 2 bulbs be better? I was told that 2 bubls might make it too hot. Any ideas?

Thank you,

Craig

[the_one_and_only]

oops... that should be I am NOW on lighting. Sorry. :)

[Phillycsi]

2 bulbs at a lower wattage is a better idea. A MH bulb only projects approx. 2 feet of light, so one will probably cause a lot of shadows in the tank. Also one MH would have to be put in the middle and more than likely be blocked somwhat by the middle brace.

In that size tank, 2 250 watts will allow you to keep anything that you want.

2 bulbs will be hot, but if they are higher up with good venilation (fans) you probably will not need a chiller.

[Entropy]

For a standard 55g I would go with two 175w metal halides. The easiest universal setup would be two 10k 175w single ended metal halide bulbs (10k XM bulbs would be my pick), supplemented by either two 40w normal output or two 110w VHO actinic bulbs (URI super actinic VHO would be my pick). This will let you keep just about anything you want in the tank.

[the_one_and_only]

Excellent ideas. Thank you. As I look through the forums, I notice that there are a lot of different 'things' that are out there. Entropy, you suggest 2 10K bulbs, (XM bulbs at that). I have noticed that 10K does seem to be the most popular on the boards, however, I have noticed 15K also. What does the 10K or 15K stand for? Is one hotter than the other? Also, what would the difference be between a XM bulb and a 'regular' bulb?

I have also seen that somewhere between 4-8 watts per gal would be enough light, with the upper number for different corals. So, I am now leaning toward the w 175W bulbs. I was thinking of having 2 computer fans placed on the back of the canopy. I would think that would be good enough to keep things cool. Any thoughts on that?

This forum is really great - made so by the people on it.

Thank you.

Craig

[Patwa]

I have a few answers for you....about the 10k and 15K....that just refers to colour temperature.....the higher the values (15k to 20K) the more blue the light will look...the less the K value (10K) the more white the light will look.......corals grow best under low K lights (like 10K or so), but look best (imo) under higher K lights

some poeple who go for 20K lights do not even really need to supplement with actinics...some say they actually have to supplement with white lights (6500K) b/c the 20k MH bulbs are just too blue

my setup is VERY MUCH like yours....i've got a 65 gal and i've got 2 175MH bulbs installed with 2 NO actincs ....my bulbs are 14K, and they have just the right balance of white and blue imo...just perfect....

what sort of corals are you planning on keeping?

Zach.

[MattG]

the k is the color temperature. a 10k bulb is suppose to have a white appearce. as you increase the k the bulb is suppose to have more of a blue appearance. as you lower the bulb the color gets more yellow. 6.5k - yellow 10k - white 20k - bluish color. lots of others that fall somewhere in between.

XM is just a brand of bulb. Lots of choices here just find something with decent par and the color appearance you like. I prefer the AB 10k bulb but thats just a matter of preference

2 175 watters is more then enough to keep whatever you want. You could even skip metal halide all together if you dont plan on housing SPS/clams.

[MattG]

beat me to it patwa.... :rolleyes: