Captive Aquatics: An Aquarium and Ecology Blogtag:typepad.com,2003:weblog-18468072011-10-24T00:17:45-05:00A freshwater, saltwater, reef aquarium and aquatic ecology blog with beginner and advanced articles, led reef aquarium lighting info, aquarium product reviews, and more!TypePadWhat you Need to Know About Photosynthesistag:typepad.com,2003:post-6a010535f11c3d970c0162fbdf4fa1970d2011-10-24T00:17:45-05:002012-09-10T01:24:51-05:00Photosynthesis is an incredibly complex process, but luckily for most aquarists only a basic understanding is required, but the time should be taken to understand that basic definition. Photosynthesis is the “synthesizing by organisms of organic chemical compounds (Oxford Dictionary of Biochemistry and Molecular Biology [1997]), mainly carbohydrates, from carbon dioxide using energy obtained by light rather than the oxidation of chemical compounds”. Instead of consuming carbohydrates like we do for energy, photosynthesis can create carbohydrates for invertebrates and plants. More simply, this means that plant cells can use energy gathered from light to produce cellular chemical energy (ATP) and carbon products (carbohydrates) when combined with carbon dioxide. Photosynthetic efficiency peaks at around a wavelength of 430 nanometers and 680 nanometers. In order for the photosynthetic process to take place, the chloroplast (the organelle of the cell where the light energy to chemical energy conversion occurs) must receive sufficient PAR and/or PUR. If the saturation or compensation point of the chloroplast isn’t met, the organelle will not produce the optimum amount of carbon bi-products (carbohydrates), and this excess energy will not be transferred to the host invertebrate. Obviously, the compensation point is something every aquarist will want to meet at...Captive AquaticsKelvin Temperature and Aquarium Lighting: What is Kelvin?tag:typepad.com,2003:post-6a010535f11c3d970c01538ffed9b0970b2011-07-24T03:51:54-05:002012-09-10T01:28:37-05:00Beware, kelvin temperature is another mind bender! Kelvin temperature (abbreviated as K), is the scientific unit for temperature, and is often used to measure the color temperature of light, or more accurately, the measurement of the temperature of an object emitting black body radiation, also known as thermal radiation, or radiant heat as visible light. All objects at a temperature greater than absolute zero emit some form of thermal radiation, although at room temperature the wavelength of this radiation is too large for the human eye to perceive. Still confused? Think of it this way: at room temperature, your stove burner doesn’t emit any visible light. However, as it increases in energy (temperature), the energy associated with the burner increases, and the blackbody radiation the burner is emitting changes frequency, and emits that energy in the frequency of visible light, and that’s when you know it’s hot! There is a great deal to know about kelvin temperature and thermal radiation (most of it mathematical) that exceeds the scope of this article, but kelvin temperature is a very useful way to measure the color spectrum of a bulb. Kelvin temperature, in the hobby, is used virtually interchangeably with spectrum. Spectral range...Captive AquaticsWhat You Should Know Before Purchasing an LED Lighttag:typepad.com,2003:post-6a010535f11c3d970c014e862be8a1970d2011-02-19T01:07:35-06:002012-05-14T03:18:51-05:00The following musings began as a simple post on 3reef and ended up being quite long. However, I think the info is valuable to anyone in the market for LED lighting. There is much, much more that goes into an LED unit besides the diodes used. Top quality emitters can be used, but if you have supbar electronics, drivers, etc on the inside, then you have a subpar light. Sure, the diode might be rated to last 50k hours with a 30% output loss over that period, but what if the drivers used are only rated for 10k hours (plus, what are the specs of said driver: is it constant-current, constant voltage, what is the tolerance, variance range, etc?). Just because you have a spectrograph for a particular emitter doesn't mean that range is actually being emitted. What a diode produces depends entirely on the power being received, which depends entirely on...you guessed it...the quality of the power supply and drivers! So, just because you are buying a fixture with the latest-and-greatest insert-fad-diode-here, (a debatable subject all on its own) if you don't know what's attached to it, you have no idea if it's actually producing the spectral curve it's...Captive AquaticsLooking to Purchase LED Lighting?tag:typepad.com,2003:post-6a010535f11c3d970c0148c6f84805970c2010-12-22T10:46:05-06:002012-09-10T01:37:13-05:00Looking to purchase LED lighting for your reef or nature aquarium during the holidays? Before you do, ensure that the manufacturer provides the spectrograph for the unit you are about to purchase. PAR measurements are virtually useless for comparing LED lighting, one can only compare using PUR. This is most easily done by comparing spectrographic data between diodes or fixtures. Any reputable manufacturer will provide you with either a spectrograph of their fixture or of the diodes they are using. Beware of those that only provide PAR plots or provide no info at all! More info: - Switching to LED Lighting - What is PAR? - What is PUR?Captive AquaticsT5 Spectrums: Choosing the Right Bulb for Youtag:typepad.com,2003:post-6a010535f11c3d970c013488d6b558970c2010-11-10T00:01:00-06:002012-09-10T18:56:28-05:00Since I use T5 lighting over my farm system, I'm always comparing different bulb colorations to use in different combinations. The spectral graphs of some of these bulbs are a pain to find sometimes, so here they all are in one place! For metal halides, a lot of people tend to model their T5's after Phoenix 14k's and Radium 20k's. You can find the spectral graphs for both from Sanjay Joshi's unblievably helpful study. The Grim Reefer from ReefCentral has done some PAR analysis on several bulbs, that you can find here: http://tfivetesting.googlepages.com/par. I am only looking at Giesemann and ATI bulbs at this time as well as KZ's Fiji Purple, if you would like to see other bulbs here please feel free to send us the spectrographs. White Daylight Bulbs Top - Giesemann Aquablue Plus - An OK bulb, but is A LOT yellower than they claim, to me this thing looks more like 8-9k. This bulb is good for SPS and LPS, but has a tendency to brown out some SPS and stress LPS. I used these for a while before switching over to the ATI's and have never looked back. Put one of these side by side...Miguel TolosaHow to Choose and Compare LEDs - They're Not Metal Halides!tag:typepad.com,2003:post-6a010535f11c3d970c0133f5b32dbf970b2010-11-09T01:24:40-06:002012-09-09T07:38:54-05:00Whenever a new lighting technology comes along, hobbyists tend to attempt to compare it to a previous and more familiar technology. This time around, LEDs are getting compared to metal halide lighting a lot, but it just doesn't work. We all know we don't exactly use the scientific method in our hobby. Terms such as watts per gallon, intensity, and brightness get thrown around all of the time, even though they mean absolutely nothing useful to us or our coral. So, what's to be done? In fact, LEDs can't even be compared with the use of a PAR meter (the PUR of the diode is what's important!)! However, I'm digressing from the point: the point is that using MH as a tool in which to compare LED lighting to is a misnomer. MH lighting is a 'single point source light', meaning all of the light is emitting from one source in one location (in contrast, a flourescent tube is a single source, but the light is emitted from the entire tube, not from a single point). LED lighting, however, is 'multiple point source' lighting, which means several sources emit light from a single point. This is a huge difference in...Captive AquaticsThe Aqua LED: Why Aren't Manufacturers More Transparent About Their LED Light Output?tag:typepad.com,2003:post-6a010535f11c3d970c01348750fdab970c2010-09-14T03:25:38-05:002010-09-14T03:39:16-05:00Today I received an email from SolarMax that simply contained this flier (click for full size) about a product that is apparently new, and called "Aqua LED", and uses "Special developed SMD-LED chips". If my sarcasm isn't apparent, I'll say it straight: manufacturers need to give us more information than what's in this flier if they expect anyone to purchase their product, as most of us like to make informed decisions (from information written in gramnatically correct English, I might add). This issue of a lack of information applies to more than just SolarMax, and has created a false environment where only a few diodes are taken seriously by hobbyists - and this shouldn't be the case. This flier provides virtually no useful information - all LED product manufacturers should supply information about the light that their fixture is emitting, at the very least, not to mention other basics such as warranty info, mounting options, etc. I don't care what type of diode SolarMax is using, just like I don't care what kind of diode Samsung puts in my LED TV: as long as the picture quality is good, it doesn't matter. This is also applicable in our hobby: if...Captive AquaticsAquarium Lighting and CRI - What is CRI?tag:typepad.com,2003:post-6a010535f11c3d970c013487454b77970c2010-09-12T23:09:44-05:002010-09-12T23:14:49-05:00CRI, or Color Rendering Index, is a somewhat dated term used to describe how accurately a given light will protray colors when compared to a reference light of the same color temperature. While not typically used or measured for aquarium lights, this term has gained renewed interest due to the recent explosion in popularity of LED aquarium lighting. CRI is measured on a scale from 1-100, and reference light sources for the measurement of CRI vary on color temperature, as determined by the International Commission on Illumination. Because spectral output can vary across a given color temperature, it is the kelvin (black body radiation) temperature that is used for comparison, and the CRI of two or more sources can only be compared if they have the same color temperature. The closer to 100 a light source's CRI is, the more accurately it will protray colors. If the information is available for comparison, choose the lights that emit a CRI of 89+. For more information on light, see the rest of the articles in the Lighting Lab!Captive AquaticsPUR and Reef Aquarium Lighting: What is PUR?tag:typepad.com,2003:post-6a010535f11c3d970c0133f3ba3107970b2010-09-03T23:59:30-05:002010-11-07T01:44:57-06:00PUR stands for Photosynthetically Useable Radiation. PUR differs from PAR because the basic definition of PAR is any light in a specific frequency range. PUR is the usable portion of PAR, and different photosynthetic species will have a different PUR range to which they respond. For example: you are given a choice to illuminate your coral with two different lights, each with the same PAR value. However, one of these lights produces energy that peaks at 450nm, or the blue spectrum, and one peaks at 590nm, or the yellow spectrum. For zooxanthellae in your coral's tissue, the light peaking at 450nm will have greater PUR than the light that peaks at 590nm, although the PAR numbers are the same. PUR is a much more useful way to compare LED lighting than any other method. Most LEDs emit excellent PAR, but often only ~50% of the PAR is PUR. The higher the PUR:PAR ratio (check the spectrograph!) the more effective the LED will be for lighting photosynthetic reef invertebrates. While PUR is tough to measure, it's much easier to figure out when comparing the below absorption graph to the spectrograph of the light or light fixture in question:Captive AquaticsPAR and Reef Aquarium Lighting: What is PAR?tag:typepad.com,2003:post-6a010535f11c3d970c0133f2c8dbd1970b2010-08-02T01:00:00-05:002010-11-07T01:42:45-06:00Photosynthetically Active Radiation, or PAR as it's commonly called, is a term that's widely used in the hobby, and is often not well understood, especially when applied to LED lighting. When used correctly, PAR information can be very helpful in determining the best way to light a reef aquarium, and where best to place corals, clams, and other photosynthetic invertebrates. When misunderstood, it can lead to unnecessary and costly lighting purchases and have detrimental affects on your reeef aquarium! So, what is PAR? This can be a sticky subject, so let's keep it simple and practical for us reef aquarists! For our uses, PAR is the number of light quanta (particles of light, called photons) that fall in a square meter over the course of one second, that are in between the wavelengths of ~400nm-600nm (nm stands for nanometer, or billionths of a meter). Still confused? Think of it as a measurement of the total amount of visible light that shines on a square meter when you start a stopwatch and hit stop afer one second. That's PAR in a nutshell! Why is PAR important? PAR is important because it is roughly the measurement of how much usable light energy...Captive Aquatics