DIY Lighting Question

[wlz_3]

I'm going to attempt to construct a metal Halide system myself. I've been researching and I just want to make sure I'm making sense of what I'm reading. Currently I plan on purchasing this bulb
Ushio Aqualite 400 Watt Metal Halide Lamp 10000K Aquarium Light Bulb - Ushio UHI-S400AQ/10

My question...
Is this the correct Ballast for running the above bulb
Buy our 400W Metal Halide Quad Tap PS M135/M155 Ballast by Venture Lighting Corp at GoodMart.com

Any info will help, I just don't want to get all set up and woops it doesn't work.

Thanks,

Luke

 

[ccCapt]

Looks like that combo will work. Pulse start ballast and pulse start bulb.

What size tank is that going on?
Any resaon in particular you are looking at that combination? For a 400w 10K bulb, that combo has really poor PAR. It's only about 117 PPFD, plus the CCT (actual color temp) is around 7300k. It will look very yellow.
An XM 400w 10K bulb, using the same ballast has 179 PPFD and the CCT is around 12000k, so it will be a crisp white color.

 

[wlz_3]

Larry,

How much does the Color Rendering Index play into the colors of the tank? That bulb is rated at a CRI 90, which is the highest.

 

[ccCapt]

CRI is the Color Rendering Index. I don't claim to be a lighting expert, but the higher CRI, like 90, means the bulb is able to reproduce the colors it was meant to produce very accurately. I think all aquarium mh bulbs are CRI 90. The lower Kelvin temp bulbs, such as those in the 3000k range usually have a lower CRI, around 80.
CCT is Correlated Color Temp. This the the actual kelvin temp of the bulb and what it will look like to the eye. Generally a 5000k bulb will look very yellow, a 10,000k white and 20,000K blue.
PPFD is Photosynthetic Photon Flux Density. This is the amount of photosynthetically available "light" in a defined area.

 

[wlz_3]

Actually most are 65-70, thats the reason I was looking at this one, most of them don't go higher than 70, Now I'm not 100% on that, but I spent about 2 hours yesterday researching it. This is the link I found regarding the CRI

http://www.donsbulbs.com/cgi-bin/r/d.pl?define=CRI

Ideally I'd like to find a 400wtt, CRI 80+, with 10,000k, looking online though, I'm having trouble finding the high CRI.

 

[ccCapt]

I never looked at CRI and of all the tests and reviews I've read, CRI is very rarely, if ever mentioned.

Actually most are 65-70

Not that I'm doubting you, but I don't know where you got this info. I don't see CRI listed for very many bulbs, but here's an example.
400w 10k Hamilton - Color Rendering Index of 95
Iwasaki bulbs (pdf sheet) - CRI range from 85 to 96 depending on the bulb

Can you link to the bulbs with that low CRI? I would just like to see which bulbs they are.

I would suggest you not worry about CRI. Here are the results from Sanjays test of 400w MH bulbs on a pulse start ballast. Note the PPFD and CCT. (I'm not sure why all the bulbs don't have a CCT listed)

 

[wlz_3]

Thanks for the information, I wasn't sure if I was reading this stuff right. Thanks,