CRI and Kelvin

[Jer-]

Hi..

If i was to get an energy saver bulb for a Planted tank, should i jus focus on the Kelvin rating? I know that Kelvin is a measure of the color temp of the light but CRI is the spectrum, and isnt spectrum more important?

I would need to get a light of FULL SPECTRUM, as in High CRI for good plant grwoth right? or is that incorrect?

Would a light of 6500K but low CRI Rating be good for plants?


THX
cheers.

 

[Lateral Line]

It would be okay for the plants, yes, not ideal, but okay. Low CRI lamps tend to have very spiky spectra. A typical tri-phosphor lamp will have an emission peak in the red, one in the green and another in the blue.

These will merge to give a combined colour temperature of the right level, and the peaks, (the red and blue), will be within the photosynthetic range.

Where low CRI comes in is the appearance of the tank. Things are coloured because they reflect light at certain wavelengths. If the wavelength isn't there, they won't reflect it so the colour of the item changes somewhat.

Chlorophyll have quite broad absorption curves and by putting energy in at just certain bands, the chlorophyll is not being used as efficiently as it might be, but that is rarely a big problem.

 

[Jer-]

Thx lat line.

ok so wot i think i read is-

Plants are ok with low CRI, not ideal, but ok.
low CRI jus means that things may not look at naturally colored.
I dont get the spectrum bit tho. so low CRIs have spikey sepcta, which means some wavelengths are absent or very low and thus the unnatural colors.
but the low CRI will not effect the photosynthetic process of plants???

Sorry lat line but can you please explain wot u mean to me again?
very sorry.

thx

 

[Jer-]

I found a site that sells 5600K bulbs with a CRI of 76.

is CRI of 76 average?

Please help me by choosing the company you would buy bulbs from.

company one- tells me the CRI

Company two- doesnt tell me the CRI.

thx. I am confused as to where i shud buy it from.

I cant find it in lighting stores here around poznan so i have to prder online.

 

[Lateral Line]

You could always e-mail the second firm and ask them if they know the CRI, or for their suppliers site to look it up. I'd be suprised if the two were very different.

Make sure if buying lamps of that type from the UK you specify the right endcap. I'm guessing you use ES, (Edison Screw), lamps in Poland, (I've been to Poland, but never really studied the lamps!). The standard lamps in England come with a BC bayonet type fitting, they will not fit in a screw lamp holder.

 

[Jer-]

cheers lat line.

I will try asking...if they dont reply then i know who i am gonna go with!

 

[Dubby]

Thx lat line.

ok so wot i think i read is-

Plants are ok with low CRI, not ideal, but ok.
low CRI jus means that things may not look at naturally colored.
I dont get the spectrum bit tho. so low CRIs have spikey sepcta, which means some wavelengths are absent or very low and thus the unnatural colors.
but the low CRI will not effect the photosynthetic process of plants???

Sorry lat line but can you please explain wot u mean to me again?
very sorry.

thx

CRI is more to do with the human eye than plants. We see a spectrum that is more in the green range. Plants do not readily absorb light in this spectrum. Hence their green colouration.

So a high CRI means a good colour rendition to the human eye. A plant bulb such as Grolux will have low CRI. EDIT: CRI has no direct bearing on the photosynthesis process.

You should ideally go for high lumens (or lux), a K rating around 6000 and high CRI so you can see the plants tastefully. Most triphosphor bulbs these days have a CRI closer to 90%