# Buying new 48" bulbs



## vrb th hrb (Feb 20, 2010)

Hey, just looking for some experienced advice on buying new lamps. 

I have a standard double strip light flourescent fixture and the bulbs are older than dirt. Just looking for some advice and the best bang for my buck, my tank is planted with a few low light varieties, I supplement with excel, flourish and root tabs.

thanks


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## BillD (Jun 5, 2006)

A tube in the 5000K (philips Natural Sunshine) to 6500K (Philips Ultra Daylight) is available at Home Depot in T12 and T8 for between $3 and $4 each. Both will grow plants well.


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## bae (May 11, 2007)

Real fanatics replace their tubes every six months or so. If you wait for them to show dark areas near the ends, you'll be delighted at how much more light you get from new tubes!

I agree with BillD that sunshine (5000K) and daylight (6500K) are both good. Personally, I find the daylight a bit too blue for my taste, and I also use cool white, aka bright white (4100K). You can use two different tubes to get a blend of light. Plants will grow well under any of these, and they're all inexpensive.


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## BillD (Jun 5, 2006)

I kind of like the 5000K better also. However, in T8 the Daylight (6500K) has better Colour Rendition, while in T12, the Sunshine (5000K) has a higher CRI. To me the CRI may be more important than the colour temp for good viewing results.


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## Lee_D (Jun 11, 2010)

Are the temperatures different for different sized lights? I have T5HO's and the recommended temps I have seen are 10000K and 6700K. Should I be using something cooler on a planted tank?

Lee


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## bae (May 11, 2007)

Lee_D said:


> Are the temperatures different for different sized lights? I have T5HO's and the recommended temps I have seen are 10000K and 6700K. Should I be using something cooler on a planted tank?
> 
> Lee


Color temperature depends on the mix of phosphors in the coating of the inside of the tube. It's a confusing term. The underlying notion is that they mix the phosphors to give a light similar to that radiated by an object at that temperature. Since the actual object would radiate a range of wavelengths while the phosphors give only sharp peaks, it's not all that close, but it's a convenient way of describing general appearance to the human eye.

10000K is used for reef tanks. It's quite blue. Since clear water absorbs longer wavelengths more than shorter ones, at depth natural light is mostly blue. This isn't particularly good for plants, so you're better off with tubes that give a better mix of wavelengths.


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## vrb th hrb (Feb 20, 2010)

thanks for the advice, going to pick up some new bulbs next week


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## vrb th hrb (Feb 20, 2010)

also to chime in about colour spectrum, in my experience growing indoor plants, for vertical growth blue and green is the best spectrum(which I got from metal halides) and the best for flowering plants is in the red and orange spectrum (which comes from high pressure sodium HPS)

so just growing simple aquatic plants I guess any fluoro is fine


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