[DJ88]

HI patrick,

I try to answer your questions. Hopefully more will jump in.

1. We need to supply lighting that closely as possible duplicates that sun on the ocean.
2. We have basically 3 types of lighting that comes close to it, MH, HQI, VHO.
3. Each type of lighting has a wattage, the wattage is used primarily to indicate the depth that the light would reach and the strength of the light if a coral was lets say 12” from the bulb.
4. Each bulb has a Kelvin rating - which is the colour spectrum of the bulb. Now my understanding is that the sun has a Kelvin rating of around 5500 – 6000 kelvins.

<font size="2" face="Verdana, Helvetica, sans-serif">1. Yes. well we need to supply enough so that the corals we buy will stay alive. I prefer to give mine enough to thrive and grow. Others seem to be happy with keeping them alive. Your choice.
2.I'd say two unless you were in a fairly shallow tank. Then it's four. MH & HQI for really intense or deep tanks(even then it depends on wattage), with VHO and PC for shallower tanks.
3.Wattage is the power that the lamp is rated at. How much power it consumes from the ballast basically. Using wattage ratings to decide how deep you can go with corals is misleading. You can have 440W of VHO over a tank and 400W of MH lighting. I'd say you can keep higher light requiring corals in a 24" deep tank no prob with the MH but you'd be really pushing it with the VHO. It's more the intensity that will determine how deep of a tank your lighting is suitable for. That and what kinds of corals you want to keep. If you want low light corals VHO may even be overkill, with SPS and clams getting down to 24" with VHO may be pushing it.
4. Kelvin is the color temperature of a bulb. The color temperature of light refers to the temperature to which one would have to heat a "black body" source to produce light of similar spectral characteristics. Low color temperature implies warmer (more yellow/red) light while high color temperature implies a colder (more blue) light. Color spectrum is a different thing. That is a breakdown of the actual wavelengths of the light. Or frequencies. Thw two are a bit confusingly similar with colors to say the least but they are different. The sun is actually 5500 degrees Kelvin at noon.

The problem with measuring the kelvin temperature of a bulb is that it doesn't actually mimic the kelvin temp it is associated with. This is due to the fact that a bulb may emit more energy in one frequency of light that overpowers the others making you think that it is a different kelvin temperature. It fools your eyes. The Iwakasi 6500K does this. You think it is a very yellow bulb which is similar to the sun for temperature. You woudl think it only has spikes in the red/yellow wavelengths. Where it also infact has spikes in the violet and green. Very green. For this reason the colors given a bulb are approximate and not exact color temps. If you do some searching you will find that certain 10KK bulbs may appear to be of a higher temp than 10KK or a 14KK may appear lower than the 14KK. From what I have read the Iwasaki Aqua 50KK is more a 20KK or 14KK bulb. Anyways when you look at a 10KK bulb it looks white. not the blue that 10KK is in fact.

Now if I was to plan on a new tank, say 4’ x 18” depth x 18” width I would use the above information to make my plans.

1. Based upon Sanjay’s article I would use the 2 - 150W HQI 6500K as it seemed to have the best PPFD, (of course I don’t totally understand what PPFD is but I believe it how we measure the bulbs?).
2. I would use 2 VHO’s 96 W to help supplement the lighting since from my basic experience MH seems to have the brightest point directly below the bulb.
3. 1 would use 2 high wattage actincs 45 – 60 W, to supplement the other lighting in the blue colour range. I understand that some people like the blue look so they might have more actincs to show that on their tank.

<font size="2" face="Verdana, Helvetica, sans-serif">1. PPFD is Photon Photo Flux Density. This is the measurement of the number of photosynthetically active photons striking a given area in a given time(one square meter per second). This measurement is done between 400 & 700nanometer wavelengths. These wavelengths are what photosynthetic plants and animals use to create energy from light. PPFD is the same as PAR which you will also see. The higher the (PPFD)PAR the more useable light energy is being transmitted by the bulb or lamp.

150W HQI's are bright bulbs. The thing is if you were to read Sanjay's article you will notice that the 150W HQI's were mearured with a reflector where all the others weren't. Most people seem to skip by this point. With a reflector you are measuring close to 100% of its emitted light energy(PPFD) where without a reflector you will only measure the light that is transmitted from the bulb directly to the sensor. So a very small percentage. Throw a reflector on the other bulbs tested and you will probably find that the PPFD readings of the other MH's climb significantly. I know the 150W HQI won't appear near as bright with out that reflector. For saftey reasons you need that refector as it is also a UV shield. Mogul MH bulbs have the UV shield included in the assembly.

2. With a 4' tank since the spread of a MH is usually about 2'. Normally a VHO is used to fill in the color gaps. ie URI super actinics with an Iwasaki 6500K. Unles syou wanted only one area of intense light in a smaller area then lower light corals outside of this area. then you go exactly the route you described. Andrew has this set up now. Allowing him to keep a wider variety of soft/LPS/SPS corals in his tank than I can with the lighting set up I have. This will all depend on what you are wanting to keep in your tank. To me that is the important thing. Don't buy the lights to fit the tank first. Buy the lights to fit the corals you want to keep. My VHO's and NO's are to fill color and for when my MH isn't on. Not to fill gaps in light in the tank.

3. Buying actinics to supplement blue will depend on what you want the color of your tank to appear. Some like lots of blue. Some don't. There really isn't any one recipe for success with lighting. Figure out what you want to keep. Then pick the main lighting and look at other tanks to decided waht colors you want to see as far as lighting goes. Right now I am running one 20W actinic, 2x75W 10KK VHO's and my 250W Iwasaki. I love the look of it. While some people would go ICK. I had a 10KK bulb on here and I didn't like it. Not enough intensity for me. Maybe I'd be happy with the 400W 10KK but who knows. I am happy(for now ;) )

Does my logic make sense or do I have to much lighting? I currently have a 175W 6500 K system (1 month old bulb) with 2 30W actinics ( 4 months old), but I have a yellow tinge to my water. I would like to make it more brighter so I thought of adding 2 small compact lighting that we discussed a few months ago. I am not really looking at the new lighting to add to my colour spectrum, more of a look to the tank. Does this make sense?

<font size="2" face="Verdana, Helvetica, sans-serif">Your tank is a 33 right? Well if you find it yellow right now(175W 6500K's are yellower than the 250W) try adding another actinic. That is one option. Another is buy a 10000K bulb and throw it in. See if anyone near here runs this bulb and will loan it to you for an hour to see it with your own eyes on your own tank. If you want to add more "whiter" lights I say go for it. You can't really have too much IMO.

My last question. Does one form of light interfere with other lighting. Lets say we have a 400W 10K system on my 33G. If the lighting is not giving enough light from a particular colour spectrum and I supplement it with actincs. Would the 400W, be so powerful that it would block the rays from actinics

<font size="2" face="Verdana, Helvetica, sans-serif">The only time light blocks or interferes with itself is with coherent light sources. All of our lighting is incoherent. So if you were to throw a 400W 10KK on your tnak all that it would do is overpower the actinics through sheer intensity. THe actinic(420nm) of your actinic lamps would mix in with the same wavelength of the MH.

Did that answer everything?

An no worries. any discussion is a good one. :D

PS if there is spelling mistakes in here so be it.. My fingers hurt now. :D

[ 07 June 2002, 14:18: Message edited by: DJ88 ]