A 10,000k - 25,000k question!

[iVgOnMaD]

Just wondering, it was my understanding that the lights in the high blue spectrum like 10,000k to 25,000k were just a BETTER choice; Now I'm wondering... are they a NECESITY? I plan on using 6,500k CF lights and am worried that my inverts will die off, should I be worried?

Hope someone can help me!!




Thanxs

[Whoyah]

You don't need to worry about your anemone. Actually most of the bulbs rated with the highest PAR (closest to the value of real sun light) are down in the 6500K to 10000k range. Your anemone and any corals will probably do better under that spectrum. Most people just do not like the look of their tanks with that spectrum of bulb. Most people prefer the look of the bluer (12000+ range). Trying to strike a balance between what is best for the corals and what is pleasing to the owner is the trick.

[Jeremy Blaze]

Actually 6500k is usually the best in terms of coral health and growth. Most people go to the higher k bulbs purely for astetics.

If you have a look at Sanjays site, you will see that the higher k bulbs are much less efficent, and put of less par.

[dakar]

Here's the simplest way I can explain my point of view, and use it for arguing and backing up my research on color temps... go outside (during the day!) and look up towards the sun... what is the primary color do YOU see? Certainly not blue, although there is quite a bit of light in the shorter and longer wavelengths mixed in there.

Granted this isn't going to be a technical explanation thread about color wavelengths and such, but understand that in the wild where you may have great depths of water, the further down you go the more of the shorter wavelengths red/orange/yellow are filtered out through various means of refraction and all sorts of other cool words until finally you reach nothing but blue, indigo and violet for visable light, but this is at some serious depths...

I'm not (yet) a diver, though have done a lot of research, much of the resulsts are buried here and there on the board.... I guess I really should find the time to compile all this and create a "What is this process we call Light" and try to explain it all in english.

Long story short... 6500K Iwasaki is the halide of choice in this house.

[iVgOnMaD]

Thanks for the help. Since my tank is only 18in deep im going to go with 10x40w 6500k Compact Fluorecent, the swirly, screw in kind that they sell at Home Depot. If anybody has any suggestions against this, please say so.

Anyways if I do this, it will give me about 6.5 watts of light per gallon is this enough? I could add more lights since it is a custom hood if its suggestable.

Thanks

[dakar]

It's been done... and with some good results. The major issue is heat generated by the 'self-ballasted' bulbs needs to be vented away from the tank. Might want to take a look at the flood lamp type PC bulbs... they are available up to 6500K, and the extra layer of protection between water and lamp helps, not to mention the builtin reflector to help get the most possible light.

I ran a 29g planted tank with just a pair of the ~120w 2900K floodlamp bulbs and have never seen macro grow so fast.