What is Actinic (03) lighting, 50/50 lighting, etc?

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Aquarium Advice FINatic
Mar 30, 2004
Raleigh NC
I have done some reasearch and have found that the light on my new hood is 100% daylight, but they make ones that are 50/50. 50% daylight, and 50% 03 light. Can anyone explain to me what 03 light is? Would this type of bulb be less bright for my fish?

I used to have 50 watts of incandescent lighting, and it wasn't NEARLY as bright as 15 watts of this 100% daylight fluorescent bulb. I was told that's because fluorescent is much more effecient, but both my fish prefer a darker tank. This light is just so bright.

If I was looking for a light that looks good when it's on, but is not very bright, and I don't care about plants or anything, can you post me a link to what I should be looking for?

For example, there is an auction on ebay for a light that im guessing is 100% 03 light, with no daylight. Can someone explain to me which each of the different parts mean?

T12 Lamps 15 Watts :?: I obviously know what 15w is but whats t12 lamps?
Super Actinic R .03 :?: again, what is this 03 light? (other than it's actinic like the acronym tells me. haha)
This lamp has a Gold End :?: does that make a difference?

Thanks as always. I love everyone on this board!

Actinic 03 light is light that peaks at about 420nm. I'm guessing that doesn't tell you anything useful though 8O . It's blue light...almost violet depending on the bulbs you buy. It doesn't look good by itself. There are also 7100k blue lights. These tend to be a little brighter than the true actinics...they are sometimes labeled as actinics or actinic blues. A 50/50 is a light bulb with mixed phosphors that puts out daylight and actinic at the same time. They are not as bright because they are emitting both kinds of light. I'm thinking the best thing for you to do might be to put something under the light you have to diffuse it some. Fiberglass door screen works well. You might also try putting a strip of masking tape on the bottom of the bulb. It will be something to experiment with. A T-12 bulb is a bulb that is 1.5" in diameter. A T-8 is 1" in diameter. I believe a T-10 is 1.25" and a T-5 is about .5". The smaller bulbs are usually more intense.
My understanding is that the actinic bulbs are designed to grow coral. Like loganj said the T12 refers to the diameter. The 12 means 12 1/8ths of an inch. Rather than buying a different bulb, I would also suggest blocking some of the light you already have. A different color of bulb might be slightly less intense but probably not enough for what you want. Diffusing the light (like loganj said) would be cheeper too. You might even be able to just put a piece of cardboard under the light. Just make sure that it doesn't get too hot under there.
It does get pretty hot... but I'll try to think of some things I can do, or make a trip to the hardware store to see if they can suggest anything.

Thanks for the responses!

hashbaz said:
The 12 means 12 1/8ths of an inch.

Thanks for posting that. I knew about what the sizes of the bulbs were, but I wasn't aware of how it was determined.
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