Philips lights who's right who's wrong

[frostby]

Was at the store yesterday, and saw a 4ft flourescent bulb made by philips, labeled for plant aquaria use. Out of curiosity, I looked up the K rating at it was only 2600. The box said the wavelengths were 'tuned' to promote plant growth/absorbtion.

Why do we/you(Aq. Adv members) recommend bulbs as close to 10,000K. Do the philips engineers know what they're doing or not, and has anybody tried this bulb firsthand?

 

[R&L]

Delete

 

[hashbaz]

The K rating is a poor tool to measure measure wavelength outputs, but it is the best we have. The rule of thumb is 5000 to 10000, but I found some 18,000 bulbs whose spectrum output matches the spectrum absorption of chlorophyll better than any other I found. Intensity is more important than K rating.

With that being said, I would suggest finding different lights. I am guessing that "tuned to promote plant growth/absorption" was written by the marketing department and not biologists/engineers. I have not heard many/any people say that 2600K bulbs were good for plants.

Plants absorb more red and blue than than other colors. See if you can find the exact spectrum given off and not just the K rating.

 

[Alshain]

EDIT: NM, better explanation above.

 

[frostby]

Given all the posts and aquascape experts that DON"T use these bulbs... Good thing I passed them by. I suppose maybe it is a marketing vs a scientific thing.

 

[fish_4_all]

Well here is the best advice I can give. Don't get a bulb that is for standard house use, they won't grow plants. As for those bulbs that say for planted tanks and then oyu see a rating of 2500k, I have one of the plant/aquarium bulbs and it grows plants just fine. I would use them anytime for any plant if I could get the wattage high enough. BTW it is rated at 3500K. Most say that the scale means nothing unless you see them for yourself. Kinda like hot sauce, you don't know if you will sweat until you take a bite.

If you really want the lights that most of us know the most about, stick with daylight bulbs with a k of 6500 or higher, highest lumens you can get and a high CRI, 80 or higher. Otherwise, get the bulbs, see if the blants grow and keep them if they do, return them if they don't.

 

[Tong]

Plant and aquarium bulbs try to produce only red and blues. I think they actually produce more reds than they do blues and thus the low K rating. These have a pinkish glow to them. I have heard that some produce more blues than reds and have a K rating of 9000ish. These have a purplish glow to them.

They also tend to produce fewer lumens than typical daylight bulbs. But don't let this fool you. Lumens are a measure of how much light the human eye can see and not what the plants can use. Plant and aquarium bulbs may actually produce more plant usable light than daylight bulbs because unlike daylight bulbs, they do not have to waste some energy producing yellow and green light.

Their downside, if you consider it one, is that most people don't find the light color very pleasing. To compensate for this, most people mix and match them with daylight bulbs.

IME, they work very well. In fact, on my old 10 gallon tank with only one strip light, a plant and aquarium bulb was the only bulb that would actually grow my plants.

 

[malkore]

That's a good way to put it Tong.
the best plant bulbs don't look good to human eyes, and don't exactly highlight fish colors either...so the most common thing plant keepers do is mix n' match bulbs to get the best of both worlds.

Plants just want light...and you are better off with more quantity of light vs. quality of light.
Meaning 3wpg of 'not the best bulbs' is still gonna make plants grow faster than 2wpg of 'only the most perfect spectrum bulbs'

 

[Plantbrain]

I go with the way the plants look under the lights to my eyes.

As far as actually growing better/worse, cool whites do as well as any plant specific bulb tested in several research studies.

So.......as far as plant growth, as growth rates(biomass/unit of time), there's little differences, intensity is another matter.

Most bulb claims are marketing hype.

Recall, they sell miracle diet pills, it's a multibillion dollar industry, but it does not mean they work nor are FDA approved

Just keep that in mind when you see wonder claims and silver bullets etc.
Lighting is among the worst in this plant hobby.

Regards,
Tom Barr