Halide Lighting?

[EQCM2B]

Here I sit trying to figure out this lighting .....stuff ....... for a reef tank to eventually have corals in it. I am looking at the Home Depot and Lowes lighting sections. I find a 400 watt metal halide flood light. Do I need to be concerned with a particular spectrum requirement with this or are all metal halides the same when it come to this and if this is a good light to use, how much heat are we dealing with here. If it has an engine, wheels or tracks I got a pretty good clue about it but this whole lighting thing is overwhelming me at the moment. :oops:

[perpetual98]

You'd need to get a new bulb for the 400W halide fixture. The ones that they sell at Home Depot (I've never seen a 400W there, but then again, I never really looked) will be the wrong color spectrum and much too yellow over the tank. You'll want something between 10,000K and 20,000K which is the way they measure bulb 'color'

How much was the fixture at Home Depot?

Eric

[EQCM2B]

So is a 10K to 20K the color that is preferable for any type of lighting for a reef tank?

[perpetual98]

For the most part. A 10KK light will be very white maybe leaning a bit towards yellow (depends on your preference and ballasts and stuff) a 14KK bulb will be a bit white/blue and a 20KK bulb will appear more blue/white.

[EQCM2B]

OK, so wattage is only half of the equation with the spectrum being the other half with what ever type lighting I use, correct? So if I am right in my reading everything here I need about 8 watts per gallon and as close to 20k as I can get? If this is correct then I now know what I am looking for.

[perpetual98]

That's pretty close. Bulb color is a matter of preference. Some people run a 10KK bulb and then supplement with PC or T5 of VHO blue bulbs for that blueish look and it makes things look pretty. One of the latest things is running a 14KK bulb for decent growth and good color. A 20KK bulb will give you blueish color but the growth of corals may suffer. My guess is head over to Reef Central (boo, hiss) and look for Sanjays threads on bulb color.

[dakar]

The MH bulbs at HD are in fact 4000K, too low color temp for our use.

There are a couple of different schools of thought here.... but 6500K to 20KK are the extremes on both ends of what are most commonly used. 6500K is quite yellow and 20K is very blue. Of course it's not all color and wattage, there are a few other things to consider as well.... the bulb's PAR and CRI should be taken into consideration as well.

[perpetual98]

Yeah, what dakar said. I've got a bit of the flu so my brain isn't working all that great. :)

[EQCM2B]

Thanks for all of the info. That helps me out alot. Now what is this PAR and CRI and what do they do? Sorry to keep asking questions on this but I am clueless about this stuff and I don't like buying stuff twice if I can help it.

[jerryc]

10K the best growth especially SPS 15K the in be tween you mite say
and 20K more blue for your eyes but a little less growth in your corals

[dakar]

Jerry I'll fight you on the 10K's hee hee I'll put my 6500K saki's up against any bulb you can find for overall health and growth of any coral.

CRI - Color rendering index, scale that goes from 0-100 with 100 being as close to natural sunlight as possible.

PAR - Photosynthetically Active Radiation, this is what our photosyntetic animals live on. The higher the PAR the more 'food' for them. Also the higher PAR can be looked at as it *generally* means the deeper into the water light is able to penetrate (with more of the color spectrum).

[jerryc]

I agree just left it out because so very few use it anymore.

But for growth its the top end

[EQCM2B]

Thanks for all of the help folks. Now I think I have a good idea of what I'm looking for.

Thanks

[EQCM2B]

The 400 watt metal halide at Home Depot was 197.00. Sorry i didn't answer sooner I didn't see the question. They also have a 175 watt @ 160.00 and a 70 watt lamp @ 117.00.