Lighting K-ratings?

[fearlessfisch]

I'm wondering what Kelvin-ratings people here prefer for their aquarium bulbs. According to my catalogue, they can make a big difference in how a tank looks, but I've never been able to compare them side to side.

Have people here tried different types, and which is your favorite and why? I am thinking mostly about aesthetics, although I realize plant growth is important too. Also, if you had a double light strip, what 2 bulbs might you choose to put together?

Thanks for your opinions.

 

[An t-iasg]

I have read that any rating from 5000K to 10000K is good for plants. I got two different bulbs, over two different tanks, to check out the color temperatures and the visual difference. Both bulbs are 9 watts, over a 5 gallon tank, and the plants in each tank are doing well. The gravel in both tanks is a mix of assorted browns and tans, with some black and pink for an accent color. It's Spectrastone brand, "Blend O' De River".

One bulb is 6700K. It makes the white stones look yellowish, but the plants are a nice bright green. The other bulb is 10000K. It gives an overall bluish tint to the tank, and there is no yellow tint at all in the gravel. The plants still look nice and green. It seems a little "dimmer" than the 6700K tank.

I don't really know which one is my favorite. I held the hoods over each tank, and I decided that the 6700K bulb brought out the best color in my purple/blue betta, and the 10000K better suited the purple/red betta. The 10000K bulb made the purple/blue betta look washed out.

I do have some pics of the tanks, but they are not resized. I'll work on that and post pics.

 

[fearlessfisch]

I would love to see those pics. Thanks for taking the time to describe this. This is exactly the kind of information I was looking for.

 

[squealor]

I recently changed lighting (for my plants) to a 9000+k bulbs and my serpae tetras (normally really red) look washed out. Not as brilliant as before, but my plants are going nuts! They have visibly grown in a short period of time and look amazing!

 

[malkore]

5,000K is rather yellow
6,700K looks more white, but has a tinge of yellow
8,800K looks white (hard to find though)
9,325K looks very pink/purple (special kind of plant bulb)
10,000K looks white, but has more blue in it (easier to see the blue when compared side-by-side to an 8800K)

actinic lighting is a special blue spectrum bulb, mainly for marine tanks, but they can be used alongside the other bulbs listed above to accent your fish. A true actinic bulb will look white, like a normal bulb, when now powered up. when switched on, it's a weird blue/purple, sort of like a blacklight, and it will make marine inverts fluoresce.

 

[fearlessfisch]

Thanks very much for all the responses--they were very helpful. I ended up buying one 10,000K and one 6,700K. I hope that together they will color the fishes nicely and get rid of any yellowish tinge to the sand.

 

[Zezmo]

My lighting fixture has 4 of the 22"x65w PC's. It came with 2 actinics, and 2 6700k/10000k 50/50 bulbs. I replaced the actinics with 2 of these...

65W x 8800K, 22" - Square Pin base
http://www.hellolights.com/55wat8822jap.html

They were on sale 2 for one when I bought them, and are still 2 for 1... at about 12bucks a piece you can't beat the price. Since each PC is really two tubes that gives me... 2 tubes 10000k (which are in front), 2 tubes of 6700k (in the middle) and 4 tubes of 8800k (in the back).

I like the combo, it brings out the colors in my fish...reds and blues... and makes my plants look great too. All the pictures in my gallery were taken without flash under this lighting.