Aquarium Lighting

I personally hate this topic. It's what I feel is the least organized and hardest topic to find accurate scientific data on across the entire internet. Aquarium lighting. As you may remember previously, aquarium lighting is very important. It will effect how algae grows in your tank, how invertebrates such as anemones will grow as well as corals! Some people claim your fish are even healthier with the right type of spectral radiation! Not to mention your fish will shimmer and look prettier under the proper lighting. To be honest with you I really didn't know too many specifics about aquarium lighting before researching for this tank. It's a bit convoluted at times and I frankly got most of my preferred information off of this site. So, lets take a look at all this. I forewarn you I will have both option and fact in the article and you're more than free to argue any points with me. In fact, I'd love to have a few more opinions on the matter...

So to begin what is light? Well, light is a particle (photon) that acts like a wave. Like all waves, light has a wavelength. If you don't know what a wavelength is you're already in trouble for this article. There are many different types of waves, X-rays, gamma rays, infrared waves, radio waves, but the type were concerned with is a small set called "visible light waves." These are the waves which we see as colors in case you didn't infer that. So why are these waves so important? Well for starters, visible light waves are the ones we "see" as color. Color is nothing more than your eye's interpretation of a wavelength of light.

Let me show you. As you can see in the photo each color has different numbers listed for it. The numbers listed are the wavelengths associated with that color in the visible light spectrum. So for example green is listed at a wavelength of 550. The wavelengths are listed in the units nanometers (nm) which is one billionth of a meter. So super tiny. You can also See the wavelength listed as "Å" which is a unit called an angstrom. Ten angstroms is equal to one nanometer. To give you a scale reference atoms tend to be between 1-100 angstroms in diameter. Were talking atomic here folks.

The the way in which light works is a wavelength of light strikes a molecule. The molecule can either absorb or reflect that wave. If it is absorbed then whoopie! If it's reflected then that wavelength can travel to your eye where you "see" it. So when you look at green grass it's not green because grass likes green wavelengths but rather because it reflects green wavelengths away!

So, lets talk more about grass. Or more specifically the molecule that gives grass it's green color. Chlorophyll. Chlorophyll is a molecule inside plant cells which can convert light energy into food energy, as you know. It does this by absorbing certain wavelengths of light. This is a chart which shows the colors of light that are absorbed by some chlorophyll molecules. The higher the peak the more the molecule absorbs that color. So as you can see, chlorophyll tends to prefer the blues/reds and doesn't absorb too much of the greens (again, hence plants tend to be green due to the reflection of green light).

Well I'm obviously not growing grass in my tank, so why does this matter? Well, I will be growing other things (hopefully) such as coral or anemones. These creatures have photosynthetic bacteria that live within them. They form a symbiotic relationship- the bacteria feed the animal and the animal keeps the bacteria safe. So, lets say I buy an a coral. The bacteria in that anemone prefer wavelengths in the blue/red spectrum and uses this type of light to create food. If the lights in my fish tank produce every color but blue/red my coral won't be able to photosynthesize and it will in turn starve. This is why it's so important to pick the right lights. If you have the wrong ones you simply won't be able to feed your photosynthetic creatures.

So you might be thinking "Well Ross, last I checked fish weren't photosynthetic, who gives a shit." Well first off watch your mouth, don't talk to me like that. Secondly true. In general your lighting is picked to cater towards anemones and corals. If you don't have either of these it doesn't really matter as much. It's generally views to be the pinnacle of aquarium prowess to reach the point where your tank can handle these creatures though. So I will eventually be hoping to reach a point where I can try my hand at them. Not to say I will, but if my tank is healthy enough why not?

So, these seems rather simple now, right? I just simply grab some lights that produce spectra in the blue/red region. I wish it were so simple. You see, most of the time when buying a light bulb the emission spectrum is not listed. Or at least I haven't seen as many as I'd like. Often suppliers list whats called the "Color Temperature" of a bulb. Let me explain...

So, you're camping. You're making a fire and toss some logs on. While burning you notice the embers are glowing. Glowing HOT! Why is that? I mean, wood doesn't glow. And when your embers cool off they're not red/orange are they? Well there's a reason. It's called color temperature. As objects heat up they eventually reach a level where they begin to glow. They begin glowing red which is the least energetic color (it has the longest wavelength). Then orange, followed by yellow (decreasing wavelength, increased about of energy required to produce that wavelength). Theoretically if you could heat those coal up hot enough they're glow green, blue etc. The color the object glows is related to the temperature, get it?

Color temperature usually ranges from 4000-20000 Kelvin (Kelvin is a unit of temperature. Think of it as Celsius if you're unfamiliar with Kelvins). The lower end (4000ish) is typically a reddish glow, whereas 10000+ is typically a bluish glow. But, I personally have problems with this system.

Lets say I have a have a light which has peaks in the red and blue range. I would be emitting both red and blue radiation but what would that look like? Purple? Some other color? Since a color temperature only refers to one PURE color I'm not sure it would accurately reflect any information regarding a mixture of colors, would it? I'm not positive. I cannot find any direct relationship between Color temperature and wavelength. I've found come crazy mathematical formulas but I do not have the calculus prowess to solve these equations. Ultimately I want to be ensured the bulbs I buy are producing light in the blue/red spectrum. Color temperature does not assure me that at all. It has a generalized correlation but I don't think we can draw accurate conclusions from that, can we?

So right off the bat color temperature is of little use to me personally. There is another measurement people sometimes use called PUR (Photosynthetic Usable Radiation) which ultimately says "how much of the light given off can be used my creatures for photosynthesis" which is exactly what I'm looking for! Sadly, most places do not list out a PUR rating. I did however find this website. This site is realistically the holy grail. I has done all the work I could ever ask for. It's simply beautiful. If you're truly interested in understanding tank lighting this is pretty much the best resource I've ever seen!

So a higher PUR value simply means a higher number of photons will be produced by the bulb in the visible light spectrum needed (red and blue) to produce photosynthesis. Does it list the specific nanometer peaks? No, but it's about as good as it's gunna get. And I'm not going to complain.

Finally. I can stop blabbing on about aquarium light. You wish you were so lucky! We're not there yet. So, I got some lights with some nice PUR values which means photosynthetic creatures should be nice and happy but how does the tank look? I mean, is it worth having a tank with healthy corals if they look like shit? Let us delve into the wonderful world of lumens.... Please look at the accompanying graph. There are two traces here. The first is the action spectrum. This is the spectrum of light that photosynthetic animals require (aka the PUR curve). The second trace is the phototropic curve These are the wavelengths of light the human eye sees most effectively.  The higher the peak the better the human eye can observe. You'll notice the closer you get to the end of the reds and blues the worse the human eye sees (makes sense since the human eye cannot see infrared or ultraviolet at all). So what does that mean for the aquarium?

It comes down to measuring whats called lumen. When measuring lumen you're measuring the amount of light that is present in the visible HUMAN spectrum. So one million photons in the blue spectrum would not look as intense as one million photons in the green spectrum because humans pick up green better. Follow me? So we've spent all this time getting lights to feed photosynthesis and now the tank might not look bright enough! So ultimately you need to keep in mind the total lumens in your system. More lumens = more aesthetically pleasing to the eye.

Hoo boy. Okay now I think I'm done. If you've made it through all this you're a real trooper. So as I said before lighting is a bit convoluted. It's tough to get the right info about them and frankly it hurts me to try.

So what did I end up doing? Well honestly I did a bit of research and went online and bought a few T-2 fluorescent bulbs. A 6500 Kelvin lamp and a 15000 Kelvin blue lamp. This was before I had done a really thorough job researching though. I think the red/blue wavelengths might end up being okay I just wonder if the intensity (number of photons/second) will be enough for any photosynthetic creatures. So, I'll hold on to these guys for now. If and when I get to corals I'll probably upgrade to some metal halides. They do look pretty though!




Day 5

Cost of supplies- 70$ two T-2 fluorescent bulbs

Total cost of supplies- 470$
Total cost of tools- 110$