Metal halide Question

[is_that_a_fish]

I was wondering if you can buy metal halides from home depot. Is there anything different about them compared to metal halides at pet stores. Thanks

[GLXTRIX]

you can, although the light spectrum isnt going to be the same. Most halides that are sold at HD are around 5K-6500K Most aquaria bulbs have a temp range of 10-20K

[Loverotties]

Dito The fixture ok but not the bulbs.

[GLXTRIX]

I was actually looking at the fixtures to somehow retro fit my 70W HQI into, but I found a desklamp. Tho I'll prolly redo it seeing as I want to add antitcs somehow.....hmmmm.

[is_that_a_fish]

If i use the bulb what will the major problems be. because i dont see a real difference in the way their made.

[GLXTRIX]

they arent made differently, they just emit a different wavelength of light. For instance, if you had a FW planted tank, those lights would be great for them. The different color range that the light puts off will most likely leave your corals starve, bleach then die. Lots of corals use photosynthesis to make most of thier food and they need a certain range of light rangin from 10K-20K The higher the K rating the better it is to have for a deeper tank, those wavelengths cut thu water better and give the deeper corals the nutrients they need from the light. At best that light will give you an abundance of great looking algea

[is_that_a_fish]

oh ok, so the higher the k the better it is for the corals etc. and the ones at hardware stores dont have the high k levels. Alright thanks. Dont want to spend money on something that wont work. thanks again.

[GLXTRIX]

it's not always true that the higher it is for your corals. Lighting esp dealing with MH's gets kinda tricky. A lil rundown, and please other people chime in to add to what I say, or even correct me if wrong. A 10K MH will get the best growth accross the board with tanks in the 50g and lower, mainly due to the tank only being so deep. You add antitics not only for supplimental light, but it also penetrats the water more to ensure light it getting to corals who require more lighting (sps) Lighting also is based on what the specific individual likes to see. A 10K lamp will be white with a hint of yellow, 13-15K will be that but have blue to it and 20+K will hold more of a blue color. MH's also rate PAR, which quickly means how much light is actually penetrating thu the water and raching the bottom of your tank ( I believe) The light at HD is rated at 5-6500K that light will be more reddish yellow, that certain type of light will help aid in the growth of FW planted tanks and all kinds of algea in SW tanks. Those type of lights are usually used in refugiums or sumps of a sw system to aid the growth of macro algea, tho most people just use pc's or flourscents not MH. In short, if the HD light is on your main disp tank, it will grow algea and possibly not be enough light (temp wise or "K") that your corals require for phtosynthesis.

[garvondavis14]

don't a lot of ppl recommend 6500k for sps?

[is_that_a_fish]

ill just go with a 10k or 20k light seeing as it will be better. thanks for the info. Luckily i didnt go ahead and buy it thinking it would be ok. thanks again everyone.

[tobbob]

when I went w/ 2 20K 250 watts on my 55 I noticed less sps growth & more algea but the blue shimmer was kewl. I'll stick w/ 12k or 14K
imho
Bob

[GLXTRIX]

this is true, sps does use 6500K but anything less than that has too much yellow and red spectrum, wasting much of the light because SPS does not use these spectrum for photosynthesis. This "wasted" light, in turn, can spawn algalgrowth. Some use a 6500K bulb with 10K and some antitics as well. Tho this tends to get pretty expensive, unless you have deep pockets. This also revolves around the whole aesthetic feel of the light. most dont care to have the yellowish look that a 6500K will emit, unless they offset it with the app. lights.

[GLXTRIX]

i'ld say look at articles on light in fish forums, wether it be here or somwhere else, learn about what light will do with your tank, and what you are planning to fill your tank with. Many people just jump into light fixtures and later on learn it's not right for what they are planning on kepping.

[GLXTRIX]

http://www.coralreefecosystems.com/ltg_bulb_color.htm

here is a great site that will help with some lighting questions, as far as MH's go.

[goodfortune]

Welcome to the world of reef tank lighting...lighting, esp. metal halide lighting, tends to be one of the most hotly debated topics in the whole hobby

In short, there are several assumptions I would like to make:

1. Metal Halide bulbs which burn at a color temp. between 6,500K and 20,000K are typically suitable for use as reef tank lighting. Though Metal Halide bulbs from HD may work, you are much better off using bulbs specifically made for reef tank lighting.

2. If you have a tank up to 18" deep or are lighting a mixed coral tank up to 24", use a 175W metal halide bulb for every 2' of tank length.

3. If you have an SPS dominant tank between 18" and 24" deep, or a mixed reef tank more than 24" deep, use a 250W metal halide bulb for every 2' of tank length

4. If you have an SPS dominant tank between 24" to 30" deep, use a 400W metal halide bulb " "

5. In general, bulbs with color temps on the low end of the range produce more P.A.R, (Photosynthetically Available Radiation; the light energy corals use for growth) but are yellowish, and don't show off the sometimes brilliant colors of corals well without actinic lighting. On the other hand, bulbs on the high end of the color temperature range show off the colors of corals very well, but do not produce as much P.A.R.

6. Items 1-5 are generalizations; what may work for your setup may be different from what I've described above.

I hope I haven't added to your confusion

- Michael

Originally Posted by is_that_a_fish

oh ok, so the higher the k the better it is for the corals etc. and the ones at hardware stores dont have the high k levels. Alright thanks. Dont want to spend money on something that wont work. thanks again.