In my experiences mixing 6500k and 10000K half and half gives a very pleasing coloration to both fish and plants. I say give it a try.

 

I agree. 6500-6700K and 10000K is a nice mix.

 

Thanks. I did hear from a few sources that this mix was ideal.

So the reds will be fine?

Now I just need to find a cheap UK source of high CRI T8 10000K tubes.

For any other UK people out there these are great T8 6500Ks and very cheap too - http://www.thearc.co.uk/catalogue1.php?current_category=Fresh+Water&prod_sub_group1=Activa

And they do cheap HO T5 - http://www.thearc.co.uk/catalogue1....atalogue1.php?current_category=Fresh+Water&prod_sub_group1=T5+GE+Daylight+6500k

 

As for the T8 10000K I would suggest Phillips Aquarelle.

 

Here' another T8 combination that looks and works well IMO. It's Zoo Med's Flora Sun and Interpet's Triton (called Tri Plus now).

 

As for the T8 10000K I would suggest Phillips Aquarelle.

Thanks. I've heard that's quite a pink light compared with other 10000K tubes that are more blue. Is this true?

 

Yes, its quite intensive pink light turns the pinkish colors into red. It is so intensive that the other 6500K more whitish flos become darker. Also after a six month of use the decrease in the intensity is less than the other flos (I am comparing to Phillips 965 and Osram daylight).

 

Sounds ideal.

Thanks for the advice, much appreciated. Great to hear from a fellow European too!

 

My pleasure but I am not sure about this European identity issue.

 

My pleasure but I am not sure about this European identity issue.

Sorry, no offence intended

 

No, it was definitely not an offense. I was joking. The criteria to be accepted as a European country have been very ambiguous for Turkey nowadays. That's why I said I was not sure. This was off the topic. Sorry about that.

 

No, it was definitely not an offense. I was joking. The criteria to be accepted as a European country have been very ambiguous for Turkey nowadays. That's why I said I was not sure. This was off the topic. Sorry about that.

Ah, I see now .

 

Have been hearing quite good things about this Aquarelle bulb. Going to order some now

 

I still use the Philips Aquarelle T8 bulb. It is a great bulb for plant growth with very strong emissions in the blue and red regions of the spectrum. It is probably the most powerful of T8s except for the red spike in a Philips ADV850. It will blow away a lot of T5 bulbs (I do not mean T5HO). It is a European bulb and usually needs to be imported thru Aamsco, a Philips distributor.

 

I'd be a little leery here, When you get to 10,000K bulbs they are not as incredibly different than 6,500K. Years ago when experimenting with lights on planted tanks I found an ideal combination was using GE Chroma 5,000K's with the GE 6,500K Daylight bulbs being considerably better than straight 6,500K. This is why I'm looking at building a LED fixture with a 2-1 split between 7,500K and 4,000K LED's. There is just a little more red in the 5,000K spectrum compared to the 6,500K's. So going with a 10,000K which should have less red I did very fickle about for plant growth.

However if your more concerned about a nice color appearance then I'd say you would possible be happy. But remember everyone's color taste varies some. I have heard complaints that 6,500K make the tank look to yellow, I also heard they make the tank to blue to some people?

However going back years ago I saw spectrum charts and commutations on different bulbs from different manufacturers. The true color temp seldom was a match to the advertised K temp. However the CRI values were fairly close to what was advertised. Generally the higher the K value was advertised the less accurate it was.

If you want to go that route I'd simply change out one bulb at a time and see how the plants react to it. It should not be a drastic change that way and you can get a better idea what is happening with the changes.

Note a 5,000K bulb with a CRI over 90 will be much whiter than a 10,000K bulb with a CRI in the 70's.

 

Nonsense. The plants could care less what the color temp is. As long as a plant has the correct nanometer emission(s) and strength its happy. Don't think for a minute that one manufactures 6500K bulb is the same as any other. It's usually a marketing gimmick - do you think a GE 9325K is 9325K - no where near it. The spectral out puts can be (and usually are) quite different in bulbs of a given kelvin temp. Same goes for 10,000K bulbs. They are not the same. My Giesmann Midday 6000K bulb appears green when lit next to an Aquaflora (pinkish hue) and an Aquarelle (lavender). Never pick a bulb by the kelvin for the plant's sake; do it for what you like as an appearance of the tank.

 

I ran across these notes yesterday cleaning out an old notebook. I am not sure where they are from but it might well be an old thread newt ran a bit in the ago.

Plant and leaf development (blue) 475nm
Stem and color (red) 650-675nm
Chlorophyll –a- 430/662
Chlorophyll-b- 453/647
Carotenoids 449-475

 

I ran across these notes yesterday cleaning out an old notebook. I am not sure where they are from but it might well be an old thread newt ran a bit in the ago.

Plant and leaf development (blue) 475nm
Stem and color (red) 650-675nm
Chlorophyll -a- 430/662
Chlorophyll-b- 453/647
Carotenoids 449-475

Yes these are the three basic photosynthesis proteins. However there are actually almost a dozen of them. However they are all not found in the same plants.

The other argument is with Chlor A it can utilize light at 430nm and 675 nm but does it require both of these wave lengths, or will it simply be more efficient with both of these wave lengths. And third what is importance of the ration between these two wave lengths.

The note on Stem and color is also misleading as it is actually specific Photosynthetic Proteins that cause stem growth. Color is actually a protective layer the plant creates to protect itself from excessive light in those wave lengths.

You may ask why are plants green it is because they cannot utilize green light therefore in order not to absorb it they reflect it. It is also interesting that most red plants will not benefit from more red light as they are protecting themselves by reflecting the red light rather than absorbing it.

I realy wish that lighting would be as simple as those 1/2 dozen wave lenghts. It it were we could all buy 6 to 12 wave length specific LED's and all be happy happy happy

 

The Journal of Plant Physiology from a University study. I do not remember which U study as that thread was from ages ago. It was developed when T8s and CFs were the big thing.

 

http://www2.estrellamountain.edu/faculty/farabee/BIOBK/biobookps.html

There is good graph on the wave lengths absorbed here.

 

Below is a NORMALIZED spectral output plot for several bulbs. The ADV850 is a 32watt 5000K Philips T8 and the Aquarelle is a 38watt 10,000K Philips T8 bulb. The PLL950 is 5500K biax CF 55watt Philips bulb. You can see the spike at around 625nm is the red. The T8s have a very strong emission in microeinstiens and they blow away a popular (at the time) biax bulb.

Its useless to compare bulbs based on kelvin temp and watts (which is an input value). A normalized plot is the only way.

[/URL][/IMG]

 

As I'm looking at those charts I would want more Blue and less red. Also keep in mind that the spikes are very strong at some wave lengths and then just a about 10 nm away from the spike it drops to 1/8 the intensity.

I realize that true spectrum plots are more accurate than the normalized plots from the manufacturers but now the spikes are scaring me for these bulbs.

 

As I'm looking at those charts I would want more Blue and less red. Also keep in mind that the spikes are very strong at some wave lengths and then just a about 10 nm away from the spike it drops to 1/8 the intensity.

I realize that true spectrum plots are more accurate than the normalized plots from the manufacturers but now the spikes are scaring me for these bulbs.

This IS what the bulbs emit. No marketing gimmicks.
One reason for more red is that red light is absorbed by the water at a faster rate than blue. Perhaps the bulb's designer knew what they were doing. Red light is more easily converted by plants than blue yet they yield the same energy.

I have no idea what you are talking about or getting at by these comments. Unlike most manufacturer's spectral plots that are on a 'Relative' scale a Normalized plot quantifies the strength of the spikes. The mfg plot is NOT more accurate.

 

Yes I agree that manufacturers plots are not accurate but very normalized.

The point that scares me is that you have peak at about 435 nm and less than 1/5th the light at 430 and 550 nm. The same thing happens with the peaks at 490nm, 550nm and 615 nm. These peaks do not all line up with the most efficient peaks needed by the photosynthesis proteins.

To me this is more evidence that a more ideal lighting source can be constructed with the use of wave length specific LED's. With proper selection of bin numbers the frequencies can be selected for the best matches of the photosynthesis proteins absorption curves.

 

Yes I agree that manufacturers plots are not accurate but very normalized.

Oh! How more confusing can you be?
Manufacturers use the Relative Energy spectral plots - useless.