Originally Posted by MoneyMitch
thanks alot byron, so nice to be part of a community like this :D i definately see the "look" your talking about even the tanks at the pet store have that purplish tint to them put your pics are like night and day compared to regular run of the mill bulb. you mentioned something about home depot which is another "aquarium" store lol. anyways you said that they also sell some simular tubes at probobly 1/2 the cost lol. now do those lights also have the spectrums listed on them or it is kind of here and there with there lights.
Unrulyevil has already mentioned that the colour temperature (Kelvin rating) is indicative of the "colour" disseminated by the tube. But it is sort of hit and miss.
For about 10 years, I lit my aquaria with tubes from Home Depot. Each tank had two tubes over it, and I had one "full spectrum" and one "Enhanced Daylight" I think it was called, manufactured by Sylvannia. I had lush plant growth, it looked natural, I was quite happy. The last time I went in for replacement tubes [you need to replace any fluorescent tube every 12 months--I can go into the "why" if you ask] I found they no longer carry Sylvannia, only Phillips (at least here in Canada) so I bought a couple to experiment. The "full spectrum" I did not like [and I have gone to Hagen's Life-Glo 2 for that component, it is much better to me], but the Daylight Deluxe is not bad. It is rated at 6500K although it is very slightly more blue--hardly noticeable on its own, but combined with other types it is visible. And here it sells for $5-$6 CDN for two tubes; the Life-Glo here is $39 each.
Anyway, when I couldn't find what I wanted at HD, I started experimenting again [if you have one or more local fish stores where you deal and they know you, they will often let you buy tubes and return them for others after a couple days, very useful] and came down to the Life-Glo 2 as the absolute best single tube light, in my humble opinion. I went to this tube last October, and after 10 months my plants are still thriving under this light, and I still like the natural look of it, so I believe it is good. The only reason I mix another tube with it on the 2-tube tanks is that I can select a higher-blue tube to get better penetration to the plants on the substrate--and remember from before, blue light is the most essential, and it penetrates water best; and I have less than 1 watt per gallon, so have to make the most of it. But the Life-Glo 2 is so strong mid-range that it balances the blue very well and prevents that ghostly look. The Lightning Rod Ultimate Daylight tube currently over my 115 (over the 90g in the photos) is 11,000K which is certainly blue, but strangely doesn't look it, at least not when mixed with the Life-Glo. I'm having trouble getting this tube now, only one lfs carries them, and he told me Saturday he was concerned they might be phasing it out. More experimentation on the way, I guess.
Fish stores often use those "purplish" tubes because they bring out the reds and blues, and as I think I mentioned, fish like neons and cardinals really stand out in the bare tanks under such light--so people buy them!