04-09-2007, 01:17 PM
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It's a great post Mofo but it's not the first time I've said it on this forum. You all must take into account that the average tank owner does not have all this test equipment lying around. Keep in mind that a tank owner is already concerned about so many things they may not understand and then you throw LUX at them. hey you guys did not even mention PAR? So the average owner can relate to a somewhat simple idea of wpg since they understand home bulbs for their lamps. Get the average lay person to understand all about LUX and you are a better person then I am.
More to chew on. FLour bulbs cannot penetrate water for crap. Halide has the ability to reach into water. I am setting up a 400g 7'x3'x3' tank right now. I will be using 4x400w 12K MH and 4 72" VHO Uri super actinic tubes for color. Go ahead and get the average hobbyist to understand what I just said, and yet that isn't even complicated by lumens, LUX or PAR. I've heard it all as to what type of lighting I should get. I was told to buy 20 tubes of T5 lighting as the LUX will be super intense compared to 4 MH bulbs. Hey any of you ever priced out a generic T5 set up x 20? Oh gawd I could buy a lot of halide ballasts, bulbs, reflectors and sockets for that kind of money. So my pocketbook would take a hit for no reason at all. And after arguing online with the self proclaimed T5 King in front of an audience of about 200 people, I asked will the T5 penetrate the 36" of my tank. He sheepishly replied, no it will not. I won that round.
There are so many other possibilities and combinations, not to mention unique situations, that is is almost impossible to say that one system is better then another. Will some work in other set ups, of course they will. For example could you run 2x 150W halides over a 55g reef or 5 T5 bulbs of about 40w? Yes and both would work well. But time again has proven that the pulsing effect of halides has a life giving quality like that of the sun which produces healthy coral that is stimulated to grow faster.
We could debate this all day long.
Basically flouro style bulbs reach a depth of usuable intensity at 12", be it T12, T10, T8, T5, or PC.
Halides reach 12" at 70-150w, 18" at 175w, 24" at 250w and 36" at 400w.
So now that we've taken some of this into account it can greatly change your feelings towards Lumens, LUX and PAR in a controlled environment like a classroom and change everything in a particular case by case fish tank.
Now we can argue about what Kelvin ratings do to LUX or PAR ratings as well. Would you recommend a 6,500K bulb or a 20K bulb? And at what LUX?
What about measuring different types of ballasts? Just because a bulb is rated at X wattage does not mean the ballast is pushing that kind of power to the bulb itself. There are many types of ballast arrangements. Is a 400w magnetic ballast more efficient, or exactly the same, as a 400w electronic ballast? the electronic ballast is generally 30% more efficient. Say what? They are both rated for 400w right? So how can they be different? The magnetic ballast uses a lot of energy to convert the 120v of electricity into the usable form the light bulb can use. Ah settled then right? Nope. Mag ballasts have a tendency to overdrive bulbs thus making them brighter then electronic ballasts. So this means a mag ballast bulb burns brighter and has more LUX then the same bulb on an electronic ballast. Settled. Nope. The electronic ballast will cause the bulbs to burn more stable and give a longer usable life span saving money in the pocketbook both on bulbs and electrical savings. Settled then right? Nope. A reefer keeping stony corals might actually APPRECIATE the over driven bulbs and therefore the extra costs could translate into better growth and better color thereby justifying the added expense.
WPG is only a guide, not a rule.
If someone came to me and said " I have 40w of light over my 50g tank", I don't care what type of lighting it is, it is still to low for a coral supporting reef tank.