K rating on bulbs and Plants.

[PlantedFishGeek]

Higher light (wattage) drives growth as well as CO2 and nutrient demands. Since you are not adding any nutrients and are relying solely on fish waste for nutrients, you are likely deficient in some nutrient that are not present in fish waste, like K or micro nutrients.

I know I am able to grow moss in pretty much any K rating, from 3,000k-18,000k.

that's the thing though the difference in wattage is 1.96 in the 55g and 2.0 in the 10g so a difference of .06 wpg and the tank with the problem is the one with LESS wpg so hence why i am confused.

[VaughnH]

that's the thing though the difference in wattage is 1.96 in the 55g and 2.0 in the 10g so a difference of .06 wpg and the tank with the problem is the one with LESS wpg so hence why i am confused.

Both tanks have 2 watts per gallon, but the ten gallon effectively has considerably less, because for small tanks the lights are not as efficient. It isn't clear to me why that would be true, but it is. One possible partial reason is that the smaller the bulb the smaller the percentage of the bulb surface is actually producing light. So, your 10 gallon tank almost certainly has a lower light intensity than the 55 gallon tank.

[PlantedFishGeek]

Both tanks have 2 watts per gallon, but the ten gallon effectively has considerably less, because for small tanks the lights are not as efficient. It isn't clear to me why that would be true, but it is. One possible partial reason is that the smaller the bulb the smaller the percentage of the bulb surface is actually producing light. So, your 10 gallon tank almost certainly has a lower light intensity than the 55 gallon tank.

Ok then why at 2 wpg should i have a problem isn't that still considered low light/low tech? it just dont make sense to me. i have tried dosing a small amount of CSM+b it made no difference, so i quit dosing all together.

[defdac]

For those of you that which to understand what Kelvin is look at the color chart here:
Color temperature - Wikipedia, the free encyclopedia

The interesting part is the black curve and the markings on it. Look for example at 10000K. Now you can follow the markings up and down and now you will see that a 10000K rated bulb can be anything from greenish to white to purple.

Thus. A higher K-rating does not equal to more blue color, even if the aquarium equipment providers think so. Their Kelvin-ratings are very probably just a number some marketing guy have come up with out of thin air - "ah, this is a blue bulb it has to be very high kelvin!".

Regarding attenuation of colors in water the attenuation effect in our extremely shallow waters in our aquariums is next to nothing. The effect will not be seen until a couple of meters of water column.

Regarding what bulb to pick there is a way to squeeze out as much usable photons from a bulb as possible. But we need to learn that usable photons for humans is kindof the opposite of plants - humans are very sensitive to yellow and green colors, and not so sensitive to blue and red colors.

Lumens for example is a direct measure of human eye sensitivity and it looks like this:


But plants are unsensitive to green (obviosly since they are reflecting green!) and have a sensitivity looking something like this:


So. What you are looking for is a bulb that spends as little effort on producing yellow-green light and as much effort on producing blue and red.

That makes ordinary light bulbs a bad choice - they do not only produce alot of yellow-green light, they also waste much of their energy on producing heat.

So to make the most intelligent choice of bulbs you can take a peek at it's spectral distribution and see if it has alot of blue and red, and as little green-yellow as possible!

[PlantedFishGeek]

For those of you that which to understand what Kelvin is look at the color chart here:
Color temperature - Wikipedia, the free encyclopedia

The interesting part is the black curve and the markings on it. Look for example at 10000K. Now you can follow the markings up and down and now you will see that a 10000K rated bulb can be anything from greenish to white to purple.

Thus. A higher K-rating does not equal to more blue color, even if the aquarium equipment providers think so. Their Kelvin-ratings are very probably just a number some marketing guy have come up with out of thin air - "ah, this is a blue bulb it has to be very high kelvin!".

Regarding attenuation of colors in water the attenuation effect in our extremely shallow waters in our aquariums is next to nothing. The effect will not be seen until a couple of meters of water column.

Regarding what bulb to pick there is a way to squeeze out as much usable photons from a bulb as possible. But we need to learn that usable photons for humans is kindof the opposite of plants - humans are very sensitive to yellow and green colors, and not so sensitive to blue and red colors.

Lumens for example is a direct measure of human eye sensitivity and it looks like this:


But plants are unsensitive to green (obviosly since they are reflecting green!) and have a sensitivity looking something like this:


So. What you are looking for is a bulb that spends as little effort on producing yellow-green light and as much effort on producing blue and red.

That makes ordinary light bulbs a bad choice - they do not only produce alot of yellow-green light, they also waste much of their energy on producing heat.

So to make the most intelligent choice of bulbs you can take a peek at it's spectral distribution and see if it has alot of blue and red, and as little green-yellow as possible!

So atintic would work well considering it is heavy blue spectrum? and it seems 6500k is the highest in red and blue light so that explains the moss turn around under the 6500k bulb!

[defdac]

So atintic would work well considering it is heavy blue spectrum?

I think someone over att APC actually ran a planted tank with actinics, don't know for how long. You should see plant pearl, but the growth might be somewhat wierd.

and it seems 6500k is the highest in red and blue light so that explains the moss turn around under the 6500k bulb!

Actually 6500K is about the very neutral color of light on a cloudy day so it should contain equal amount of all frequencies.

Flourescents can't produce an even spectral distribution like the sun light, but it can mimick it by emitting tre distinct colors in equal amount, Red Green Blue. Like your monitor or TV.

6500K bulbs are average or a little above average regarding growth rates though. Tri phosphor bulbs like Aquarelle, Aquastar, PowerGlo, Triton etc emits *very* much energy in the blue and red parts of the spectrum. Don't get scared of their 10000K rating, as you have learnt it doesn't tell anything about the actual color or the spectral distribution.

[ceg4048]

So. What you are looking for is a bulb that spends as little effort on producing yellow-green light and as much effort on producing blue and red.

That makes ordinary light bulbs a bad choice - they do not only produce alot of yellow-green light, they also waste much of their energy on producing heat.

So to make the most intelligent choice of bulbs you can take a peek at it's spectral distribution and see if it has alot of blue and red, and as little green-yellow as possible!

Hi defdac
While I wouldn't dispute the findings that led to the data provided on the chart, I would question the practical application. Isn't it odd for example how the highest point in that chart is at about 420nm which happens to be the peak frequency of the actinic bulb? It makes me wonder whether this chart was produced from data from a marine algae. Based on the data alone the best course of action would be to use 100% actinic but of course that would be ridiculous.

The chart shows relative photosynthetic rates but it does not address adaptability or intensity. If a plant is grown under a certain spectral curve and then suddenly exposed to a different curve I would expect a drop in photosynthesis while the plant rearranges it's pigmentation to adjust to the new spectrum. It also clearly shows that photosynthesis under green/yellow light is non-zero so that means photosynthesis can and does occur under green and yellow light.

So how well does a plant do if grown under common office/household type spectrum? Well, here's how:


This is A reinikii (supposedly a difficult plant) and P. stelleta grown under the T5 version of common household/office building type bulb (Osram 840) in the yellow/green range. The advantage? They are 3X-5X cheaper. The result? They grow just fine. The disadvantage? The yellow cast of the tank is garish an absolutely awful. Everything looks like hamster vomit. You can see that the Althernathera which is supposed to be a red plant has a sickly orange color under these lights while the green stelleta behind doesn't look too bad.

I finally got fed up at having to look at the revolting color cast and replaced some of the bulbs with other bulb types. The plants carried on as normal and I didn't see any growth rate differences although I didn't specifically measure it.

So this shows that we don't have to pay megabucks for special designer bulbs and that we don't have to worry about Kelvin values except if that particular bulb happens to give your tank a color cast that you particularly like and can't achieve with alternative bulbs. Common household bulbs do just as good a job as any regardless of their spectral curves. You only ever have to worry about what looks good to you. If you like to mix the blue cast of actinic with some other color then go for it. If you like the red cast of Grolux type bulbs then fine. I don't have any trouble growing plants with whatever bulb type used. Each bulb gets just as hot as the next and the plants grow just as well regardless of published spectral curve. There are a lot more things that affect plant growth than spectral quality of one's bulbs. It's not even remotely close. CO2, nutrient dosing, maintenance and flow/distribution are orders of magnitude higher in importance than any spectral characteristic of some bulb.

Plants can easily grow as well even if they are raised in perfectly green light. They will simply develop pigmentation to convert the green light and to pass it's energy onto the chlorophyll. Again, I'll go back to the rain forest canopy example. What color light filters down to the plants living on the forest floor under a canopy of green? These plants only ever see green and a little yellow light and they grow perfectly fine. The intensity and therefore the photon flux density is much lower under the canopy which limits their growth rate, but that's about it.

Cheers,

[PlantedFishGeek]

Hi defdac
While I wouldn't dispute the findings that led to the data provided on the chart, I would question the practical application. Isn't it odd for example how the highest point in that chart is at about 420nm which happens to be the peak frequency of the actinic bulb? It makes me wonder whether this chart was produced from data from a marine algae. Based on the data alone the best course of action would be to use 100% actinic but of course that would be ridiculous.

The chart shows relative photosynthetic rates but it does not address adaptability or intensity. If a plant is grown under a certain spectral curve and then suddenly exposed to a different curve I would expect a drop in photosynthesis while the plant rearranges it's pigmentation to adjust to the new spectrum. It also clearly shows that photosynthesis under green/yellow light is non-zero so that means photosynthesis can and does occur under green and yellow light.

So how well does a plant do if grown under common office/household type spectrum? Well, here's how:


This is A reinikii (supposedly a difficult plant) and P. stelleta grown under the T5 version of common household/office building type bulb (Osram 840) in the yellow/green range. The advantage? They are 3X-5X cheaper. The result? They grow just fine. The disadvantage? The yellow cast of the tank is garish an absolutely awful. Everything looks like hamster vomit. You can see that the Althernathera which is supposed to be a red plant has a sickly orange color under these lights while the green stelleta behind doesn't look too bad.

I finally got fed up at having to look at the revolting color cast and replaced some of the bulbs with other bulb types. The plants carried on as normal and I didn't see any growth rate differences although I didn't specifically measure it.

So this shows that we don't have to pay megabucks for special designer bulbs and that we don't have to worry about Kelvin values except if that particular bulb happens to give your tank a color cast that you particularly like and can't achieve with alternative bulbs. Common household bulbs do just as good a job as any regardless of their spectral curves. You only ever have to worry about what looks good to you. If you like to mix the blue cast of actinic with some other color then go for it. If you like the red cast of Grolux type bulbs then fine. I don't have any trouble growing plants with whatever bulb type used. Each bulb gets just as hot as the next and the plants grow just as well regardless of published spectral curve. There are a lot more things that affect plant growth than spectral quality of one's bulbs. It's not even remotely close. CO2, nutrient dosing, maintenance and flow/distribution are orders of magnitude higher in importance than any spectral characteristic of some bulb.

Plants can easily grow as well even if they are raised in perfectly green light. They will simply develop pigmentation to convert the green light and to pass it's energy onto the chlorophyll. Again, I'll go back to the rain forest canopy example. What color light filters down to the plants living on the forest floor under a canopy of green? These plants only ever see green and a little yellow light and they grow perfectly fine. The intensity and therefore the photon flux density is much lower under the canopy which limits their growth rate, but that's about it.

Cheers,

Oh im by no means getting Designer T5 bulbs, actually to wager a guess they will be Philips bulbs, Decent quality,Decent price. I know under the bulb i have plants struggle, i thought it was the K rating but have learned that it more than likely is just a low CRI or Producing a light that the plants have a hard time adapting to, i sent an email to the manufacturer and they do not have the CRI rating as it is a test they dont run.From my personal expierence however the Same moss seems to do well under a 6500k "Twisty" energy saver bulb, the exact reason could be many, smaller tank,better light penetration,etc.

Can anyone tell me if Aquatic plants can suffer Nitrogen burn if the nitrates in the tank get to high?I know land plants can be burned was wondering if it was the same in our tanks?

[rich815]

Is there an "Ideal" K rating for a planted tank,if so what is it?

Are 10,000k bulbs good for planted tanks?

So What K rating is best Avoided in a planted tank?

If it should be a mixture What K ratings are Best?

I have used everything from 4000k PC bulbs to 6700k and 10,000k PC bulbs and now use 1 - 18,000k T5 (Hagen Power-Glo) with 2 - 6700k T5's (Hagen Life-Glo)over my 72 gal. My 10 gal has 2 - 18,000k T8 (Hagen Aqua-Glo) bulbs going. Plants grow fine in all. Except for the 4000k bulbs (which were quite yellow-warm) I barely see any difference in the light temp to my eyes viewed on the plants, though the 18,000 bulbs do look pinker than the 6700k bulbs when looking directly at the lit bulbs and side by side.

From my experience and from what I've read elsewhere it really matters little. Any difference is probably so minute as to be over-shadowed by more important things like photo-period and ferts.

[Carissa]

Worrying about K ratings with a planted tank is like worrying about a tiny scratch on a car when the engine is not running. I guess if someone was up to such a standard of perfection with their plants that everything else was working and running perfectly, it would be time to worry about K ratings. I'm not there yet. But then I guess K ratings wouldn't matter, because the tank would already be near perfect. It's interesting to learn about, but not much practical value for the majority of people.