Confused about Lighting

[Natterjak]

I've been trying to read up on lighting, but I'm getting pretty overwhelmed with the info, and having a hard time trying to figure out exactly what I need.

We have a 70-gallon tank with 50 pounds of live rock in it currently. We plan to have a FOWLR tank for a while, until we get experienced enough to try a reef. Is the lighting that came with our aquarium (and I have no clue what type of bulb it is, there's no label on it anywhere) sufficient for now?

And can anyone explain lighting to me, or point me to an article that does? I'm really confused about all these things like daylighting, having different types of lights, etc.

Thanks!

[kreach]

For a fish only tank, the lighting that came with your tank should be fine. I suspect they are just standard normal output, or NO lights... that's what usually comes with aquarium packages. You might consider switching out one of the white light bulbs for an actinic blue, it gives the tank a nicer color, IMO... but that's just aesthetics.

Once you decide to go reef, you'll need to upgrade your lighting. What lighting you will need will depend on what kind of corals you'll want to keep.

HTH

[fishfreek]

And can anyone explain lighting to me, or point me to an article that does?

I wish it was that simple. Lighting is easily the most complex part of a reef setup. There are just so many alternitives and possible combinations. Lighting is very much a personal preference thing also. As kimberly stated the lighting that comes with the tanks is usually normal output florecent bulbs. These put off light but realisticly its not much. If your not looking for the coraline growth on the rocks then really the only need for a light in a FO tank is so you an see the fish.

Once you start talking about reefs then again as kimberly said you need to think about what corals you want to keep. Different corals have differnt lighting demands. Some need very bright light and some need absolutly no light. Water flow is also a concern with corals.

When your tank goes reef you will have bascily 4 options. 8O

Metal Halide
VHO
Power Compact
T5

And of those options you can have a mixture. For example, Metal Halide with VHO or Metal halide with T5 or Metal Halide with PC or PC with VHO. The different options possible are kind of limitless but there are some better configs than others.

IMO the ultimate setup would involve a Metal Halide and VHO setup with the MH bulbs at 10K spectrum and actinic VHO's.

You could go with an all VHO setup and split the bulbs between 10K and actinic.

The K rating on the bulb also known as kelvin is what we use to determin the specitrum or color output of the bulb. The higher the K the more blue is in the light. For example a 5500K bulb will appear more yellowish than a 10K bulb. The 10K bulb will appear more blue/white. Actinic bulbs dont have a kelvin rating because most of their output is beyond our visable range. This is why these bulbs often appear simular to black lights or have a very deep purple coloration.

[Natterjak]

Thanks for the replies, that helps to clear things up a lot for me.

What's the minimum needed for coraline growth on the rocks? I would get all the lighting now, but it looks so expensive!

[loganj]

I'm not sure what the measurements are on a 70 gal...one of my maintenance customers has a 75 gal that is about 20" deep I think. It has one white 40 watt bulb (Power Glo) and one 40 watt actinic. The coraline growth has to be scraped off the front glass every two weeks when I go to service the tank. Calcium and alkalinity levels must be maintained though. You may not get much in the way of new growth, but I think you will be able to maintain what's already there with 2-3 NO bulbs. You will have to upgrade when you change to a reef. Coral Vue makes a nice MH/T-5 actinic retro kit you might want to look at when you're ready to upgrade.

[Natterjak]

Our tank is kind of unusual in that it is tall rather than wide. It's 36" wide and 16" deep...I'm not sure how tall it is, but it's probably about 36".

[loganj]

According to the math, your tank would be about 28" tall (LxWxH/231). I'm not sure NO lights would do you any good on a tank that tall. You could do a 2x96w PC for not a lot of money...especially if you DIY it. Then, when you upgrade to reef lighting, you could use the PC setup for actinics.

[TheMadNucleus]

Just wanted to correct a slight error in description of Kelvin re Light temperature.

For example a 5500K bulb will appear more yellowish than a 10K bulb. The 10K bulb will appear more blue/white. Actinic bulbs dont have a kelvin rating because most of their output is beyond our visable range. This is why these bulbs often appear simular to black lights or have a very deep purple coloration.

Actinics do have a temerature rating as do any light generating objects. However, the means of determining that are different in flourscents as it is a chimical reaction of gas molecules at the atomic level that generate the light in these bulbs. Therefore, it is more difficult to determine the temp. rating. In addition, the temperature rating would have less meaning as these bulbs do not have high CRI's (color rendering indexes). This is because by combining various substances in the bulbs we are effectively filtering the lightbulbs output, i.e. tailoring it to have a very specific spectrum.

Note that the temperature of a bulb does not exactly relate to it's color spectrum, it actually relates to the peak wavelength of light that the bulb (or object) produces. The color spectrum can only be determined by a variety of other ratings and methods. Though it is generally true that the cooler the bulb the warmer the color and the hotter the bulb the whiter/bluer the light. However, the 10,000k and 20,000k bulbs peak in the Ultra-violet wavelegths, hence visibility of the light is not related to the temperature of the bulb(object).

This formula converts Temperature to Wavelengths

WaveLenght in Nanometers = 2,900,000/ temp in Kelvin

so

2,900,000/10,000 = 290 nM

Visable light ends at about 400 nM so a 10,000 K bulb has it's peak output well outside the visible spectrum. A 10,000 K bulb actually produces a considerable amount of ultraviolet light and this is likely the reason for it's popularity in Reef systems as it increases coral organism's generation of pigments (colors) just like it will make you or I tan.

Just thought I'd throw some additional light on the subject.

Tom