Is this a good light?

[eaglesatc]

I have a friend that will give me an old light fixture that he doesn't use anymore. He doesn't keep up a tank anymore. It has 4 96W bulbs in it and 2 fans. It has 5 powercords. The lights are 2 white and 2 blue. They are about a year and a half old. So I plan to replace the bulbs. What is the difference between the white and blue bulbs? And will this be enough light in a 75g tank?

 

[Andrew]

What kind of lights? PC, VHO, T5? White bulbs are 10k and blue bulbs are 20k. There are also 14k, 15k, and 6500k which are also used. So 2 white and 2 blue bulbs will give you a 15k look which is 50/50 so white with a blue tint.

 

[ODOG]

Sounds like a 96 watt powerquad, PC's. I think it's a good starter light, but probably not enough in a 75 gallon. You could maybe get away with some shrooms and some low light loving softies, but it's stretching it. Just as an example I have a similar PC light with 130 watts over a 20 long.

 

[Paintbug]

sounds like 384w of PC lighting to me. which is more than i have on my 75g. i have some mushrooms, zoos, a colt leather for softies. my LPS corals include an open brain, neon green trumpets, baby blue candycanes, and a branching hammer. the only thing i would recommend is getting new bulbs. PC bulbs tend to loose their bandwidth after about 6 months. that can cause algae issues. other than that those will be fine for about anything you want in the softy and LPS coral range. and you cant beat the price of your lights!!

 

[Yose]

Agreed... Sounds like PCs

On another note:

The white bulbs can be anything from 5500 Kelvin to 14,000 + Kelvin.
5500 will look white/yellow - 14,000 will look white/blue

The blue bulbs are actinics and probably 460 nanometers (nm) from what you described. The 2 most common types of actinics I've seen are 460nm which are blue, and 420nm which are purple.

If you have 4 X 96 watt PCs you have some good starter lights there I would definately change the bulbs, especially if you're not sure how many hours they've been lit.

I started with a 4 x 65 watt set of PCs over my 75 and the tank did ok After about 10 months I added a 175 watt Metal Halide (MH) and a 250 watt MH. The difference was very dramatic both in the total intensity of the tank and in coral growth across the past year.

As I stated earlier, 4 X96 is a great start for a new tank but if I were in your shoes, I'd still consider adding to the total lighting as the system matures.

IMO 10,000K MH, 6500K whites and 420nm actinics look great!

Some other stuff:

1500 K Candlelight

2680 K 40 W incandescent lamp

3000 K 200 W incandescent lamp

3200 K Sunrise/sunset

3400 K Tungsten lamp

3400 K 1 hour from dusk/dawn

5000-4500 K Xenon lamp/light arc

5500 K Sunny daylight around noon

5500-5600 K Electronic photo flash

6500-7500 K Overcast sky

9000-12000 K Blue sky

The spectra below were generated using different RGB values for wavelengths between 380nm and 780nm. This was done by using a FORTRAN program that uses linear approximations for the RGB color coefficients.

HTH

 

[eaglesatc]

How did you add the MH light to the set up? The light fixture he has would just about cover half of the top of my 75g.

 

[Yose]

The PC fixture I have is a Custom Sealife (CSL) unit. The Fixture is sitting towards the back of the tank. The MH fixtures are mounted on the lid of my canopy toward the front of the tank.

When I decided to add MH, there was concern that the CSL fixture would block the MH but oddly enough it doesn't block it much at all. My tank is super bright

I'll take and post some pics for ya

 

[Yose]

Here ya go:

 

[dryice]

interesting