Question on a type of light?

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e burna

Aquarium Advice Activist
Joined
Mar 14, 2005
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Villiage of Lowell
Hi. I have a 29 gallon slightly planted freshwater tank. Right now I have 2 bulb hoods. I bulb is a black light, the other is a 2800K bulb. THey are both 24" and 20watts. I found a good deal online (I think) on a bulb. Would this be a good bulb for my tank concerning plant growth?


A standard intensity 18000K bulb that stimulates optimum wavelenghts required by plants for efficient photosynthesis. It promotes lush plant growth and enhances colors while intensifying the natural beauty of tropical fish. It has an effective enhancement of the blue, red and orange pigments to beautify aquarium inhabitants. Recommended in combination with Sun Glo or Life Glo bulbs. It is a rapid start lamp, fitting all suitable standard and electronic ballasts. This is a T8 (1") bulb.

It's 24" and 20watts.
 
Kelvin isn't the best bulb 'spec' to go by, because it's only a measure of the color of the light, not the actual spectrum
However, blacklight isn't going to be beneficial to plants, adn the 2800k is going to be a very ugly yellow, tho it will grow plants just fine.

an 18000k might be a little bit blue on the tank, but it likely has good phosphors for plant growth.
Honestly though, if you'd like to save a bunch of money (as LFS's like to charge at least $20 for any light bulb)...go to Ace hardware or Home Depot/Lowe's, and look at their fluorescent bulbs. They should have a generic Aquarium & Plant bulb, probably by Phillips or GE. Get one of those, and then look for a Daylight flourescent by any manufacturer, although if you can get Sylvania or Philllips...do it.

Mix those two, and you'll spend under $15 for BOTH bulbs, and have good spectrum for plants.

just my two cents :)
 
Thanks for the tips. What would a light that had 18000K be good for? The lady on the phone said this one was good. What was this one designed for?
 
Anything 10000-20000K is considered "daylight" or "ultra-daylight" and has been used in VHO for a long time for Marine applications.
I pick up my bulbs from walmart....in the lighting department with the regular bulbs.. LOL
 
greenmagi said:
Anything 10000-20000K is considered "daylight" or "ultra-daylight" and has been used in VHO for a long time for Marine applications.
I pick up my bulbs from walmart....in the lighting department with the regular bulbs.. LOL

Ok, I assume by the "LOL" your joking about getting your bulbs at Wal-Mart, as I don't think they have bulbs that are meant for plant growth. About your comment on the 18000k being "daylight", or "ultra-daylight", is that good or bad as far as plant growth? I would think it would be good? I'm sorry, it's sometimes hard for a newbie plant tank person to read through the lines on this. I'm just looking for it in terms I can understand. Will these bulbs help grow plants? Why or why not? Thanks for reading.
 
Ive been told that the 10000K do fine so I would assume that the 18000K might do fine as well but they are more then likely more expensive then what you need..
and yes I get the bulbs right by the shop lights and that was what I was laughing about.. they have "daylight" bulbs rated at 6500K.. the bulbs are marked with the K value..
 
greenmagi said:
Ive been told that the 10000K do fine so I would assume that the 18000K might do fine as well but they are more then likely more expensive then what you need..

I can get them online pretty cheap. Actually like 4.69 a piece. They have the 2800k for 5.99 a piece. Should I do one of each? Would it just be better to run (2) 2800k, or 1 of each, or (2) 18000k? Would the tank be darker w/the (2) 2800k bulbs then it would be with the 18000k? Would the plants grow better w/the 2800k??? Sorry, just want to be 100% clear on this. Thanks again.
 
Honestly I wouldn't run any 2800K bulbs. Walmart very likely carries the same GE/Phillips 'Aquarium and Plant' bulb I mentioned. However I avoid shopping WalMart as much as possible, due to the way they work their employees, as well as their business practices taht put small shops out of business...thus I recommended any normal hardware/home improvement store.

You can order them online, but find out the shipping cost. its probably cheaper to buy something similar locally than pay $7 to have $8 worth of bulbs shipped to you, when they'd only be $13 plus tax locally.
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malkore said:
Honestly I wouldn't run any 2800K bulbs.


You can order them online, but find out the shipping cost. its probably cheaper to buy something similar locally than pay $7 to have $8 worth of bulbs shipped to you, when they'd only be $13 plus tax locally.
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Why wouldn't you run the 2800k bulbs? You would choose the 18000k for plant growth in a 29 gallon tank? Locally they are $16.99, that's at a petstore, Wal-Mart doesn't even carry plant growth bulbs here. Every response still leaves more questions...ANYONE?
 
there with the regular NO bulbs at walmart.. try lowes, home depot, Ace hardware, True Value hardware.. it is a regular bulb.. asking the employees at lowes normally gets me strange looks.. Ace on the other hand if you ask a question be prepared to be took to the item.. :mrgreen:
 
HD here has "Daylight Deluxe" bulbs, 6500K, for ~$5 for 24" t12, iirc. I run this as noon lights in high light planted and like the color. I have 4000K and 2800K bulbs too, and it hurts my eyes after a short period of time, even when mixed with my 6700K CF main lights at higher total wattage. Since you have access to different color temps at nice prices, you should experiment and see what does best for you and your plants. I'm ordering 10000K bulbs just to mess with them -- its good to experiment with this part of the hobby, I think. :)
 
czcz said:
Since you have access to different color temps at nice prices, you should experiment and see what does best for you and your plants. I'm ordering 10000K bulbs just to mess with them -- its good to experiment with this part of the hobby, I think. :)

So buying a 18000k bulb would not necessarily be a waste then? I could run a 2800k and a 18000k and see what happens, correct? I just don't want to buy it if it's a waste.
 
A 18000k along with your 2800k may actually be a good combination as the 18 will be rather blue in color and the 2800 is pretty far down the red light end of the spectrum. Plants need adequate light in both ranges for good growth.
 
e burna - exactly. If you're looking to spend your dollar wisely without experimentation, then certainly stick to 5000K-10000K, as its the tried and true method.
 
Help me clarify what I've read above; if you had ONE bulb to use on a planted tank, what 'spectrum' would that be? The 'grow lights' bulbs from HD/Lowes/etc or something else? 6500K, 10000K or 18000K?

Is it just a matter of preference and appearance?
 
Personally, I have two 6700K bulbs over my 10 gallon, and overall I like the color temperature... but in the future I may try a 10000K just to 'whiten' it up a little more.

Given the choice above, I'd pick the 10000K, cJw. It'll def. grow plants and it'll def. look nice.

It's all aout personal choice tho, so your fav look/color may be radically diffrernt from mine. Personally I'm not too picky about these things, so I just went with one I knew would grow plants and look decent. If you're really picky, some people swear by 9532K bulbs or some weird number like that...

It's not a critical factor IMO; Success does not hang on the color temp of your bulb.
 
Kelvin doesn't mean spectrum.

Kelvin means color temperature, and is a measure of the color emitted when shone on a special black background.

While kelvin can be indicative of a bulbs spectral output, the use of several phosphor coatings in bulbs has had a huge effect on this 'indicativeness'.

As Blazer says, kelvin/color temp is not the most crucial factor in plant growth. You'd be better off with two 3000K bulbs than one 6700K bulb...intensity is most important, since most all fluorescent bulbs have a 'decent enough' spectrum for plant growth.

Ditch that black light bulb though. It IS useless.
 
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