Boston Aquarium Society Message Board

We haven't had this debate here yet

I was having this debate with some planted tank folks over the weekend and there was a mixed response.

How much light is "too much" when it comes to bulb spectrum?

I know one planted tank enthusiast who uses the 10000K bulbs and another who says that the 8000K are more than adequate. Both setups use CO2 and both folks are growing a variety of plants.

What do you folks think? And have any of you tried the (new?) All-Glass compact fluorescents? Do you like them?

thanks,

Amy

For what it's worth, plants evolved using daylight, which if I remember right is about 6000K. I've had good luck just using daylight flourescents. When I started adding CO2 the biggest change was that suddenly everything was pearling! Growth didn't really explode but O2 levels definitely went up in the tank!
I think the real secret is balance - nutrients - light - CO2.

-- Dave

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There are 10 kinds of people - Those who understand binary
And those who don't

Agreed - I like daylight bulbs.

As to the initial question - how much is too much -- it depends if your asking about lumens (PAR, etc) or Kelvin.

PAR - photosythetically active radiation - is the amount of useful light the plants get from the bulb, and is often correlated with lumens (the amount of light people get from the bulb) even if that isn't technically correct.

Kelvin - the "K" in 6500K, 8000K, 10000K, etc - is actually color temperature - ie a way of describing the "color" or spectral makeup of the light. Higher numbers tend to be more "blue" - 20000k bulbs are used in reefkeeping to add more blue light or replicate a deep ocean evironment.

As Frontfan mentioned - Daylight is somewhere between 5000k and 6500k depending on who you ask and where you are on the globe.

Generally - not always, but its a pretty good rule of thumb - bulbs with higher color temps (ie 10,000k, 15,000k, 20,000k) have less PAR than bulbs with lower color temps like 5000k and 6500k.

also - many of the 'daylight' bulbs (5000k -6500k) have better "color rendering" -- ie items show their natural colors better.


Personally - I find that "daylight" (5000k) and "super daylight" (6500k) bulbs are WAY cheaper than 10,000k or higher bulbs - especially if you're like me and buy cheap 'common' daylight bulbs like the GE Sunshine or Phillips Super Daylight at Home Depot or Lowes (etc) rather than spending twice the dough on an "aquarium" bulb that seems less bright.

(in fact, every time we blow a bulb at work and put an "aquarium" bulb over the tank, I cringe - the tanks in that store that look best have cheap daylight bulbs on them)

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Rich
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Part-time fishguy at Uncle Ned's Fish Factory (saturdays)
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Species I am currently keeping/breeding include :
Copadichromis borleyi "redfin"
Labidochromis caeruleus yellow labs
Aulonocara sp. "Lwanda"
Ancistrus cf. cirrhosus "Super Red Ancistris"
Xiphophorus montezumae Montezuma Swordtails
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(I'm in the middle of resetting and redesigning my fishroom - so things are kinda quiet)

I've been using a 15 watt single tube florescant light for a while in my 10 gallon planted tank with 20 pounds of fertilized gravel and Flourish Excel, but the plants aren't growing well. Is it the light?

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Trying to concentrate on dart frogs, African cichlids and Aphyosemion killifish (oh, and mysnake pair and reef too). I've always got something for sale, PM.

mike,
About six months ago I put a second 15w hood on my guppy 10g,( 30w total). The growth rate shot up. Now I throw vals away. The rest of my set up sounds about the same as yours.
Conrad

my favorite setup for 10g tanks includes at least one old incandescent strip light with two of the $5 power compact lights from the Walmart pet department (10w each, screw-in power compact style, narrow like the old style incandescent aquarium bulbs)

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Rich
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Part-time fishguy at Uncle Ned's Fish Factory (saturdays)
_______
Species I am currently keeping/breeding include :
Copadichromis borleyi "redfin"
Labidochromis caeruleus yellow labs
Aulonocara sp. "Lwanda"
Ancistrus cf. cirrhosus "Super Red Ancistris"
Xiphophorus montezumae Montezuma Swordtails
_______
(I'm in the middle of resetting and redesigning my fishroom - so things are kinda quiet)

We have those at Skipton's too... and I know they fit in the 15W incandescent strip fixture.

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Mmmm.... fishies.

The wal mart bulbs are ok, but Coralife's Mini Compact 50/50 Flourescents are a step up. They are around $10 a piece, they screw into an incandescent fixture, and is 10,000k daylight each bulb. The bulbs are half daylight and half actinic and it makes a really good effect in the freshwater aquarium.

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Eric - Secretary/Bowl Show Chairman