Yet Another Lighting Question

[A340]

OK, when it comes to lighting, I understand the whole 1.5w - 2w per gallon rule of thumb when it comes to planted tanks, but what about the K rating of the light fixture?

[Chrona]

OK, when it comes to lighting, I understand the whole 1.5w - 2w per gallon rule of thumb when it comes to planted tanks, but what about the K rating of the light fixture?

When aquarium light manufacturers refer to K is it just the color of the light that you see. 6700K is pure white. Higher (10000K+) is blueish, whereas lower (4000K-, etc) is yellowish. However, the spectrum put out by the bulb is more important. 6700K bulbs produced by different manufacturers can result in drastic differences in plant growth because the end "color" may be the same, but the mix colors used to achieve it are not necessarily so. However, because bulb manufacturers are usually a PITA and won't give you a full spectrum analysis of their bulbs, people just go by the K rating as bulbs between 5000K and 10000K are usually full spectrum, which are ideal for plant growth.

[A340]

That's what I thought, just wasn't 100% on it. The reason why I asked is because I am using a Power Glo on my 29g planted tank and was thinking of switching over to the Flora Glo bulb, whick has a much lower spectrum.

Should be worth a try and see what happens,

Thanks Chrona

[Chrona]

Basically any light bulb between 5000k and 10000k should be fine. No need to pay extra for those "plant bulbs" when GE bulbs have the same spectrum :)