It's really a matter of personal choice. The 6500K will be slightly more blue than the 5500K but it's a little subtle.Schism said:Which bulb will look better the 5500k or the 6500k?
I hate plunking down money on something like this when I just don't know which is best. There is no place for me to see lights like this in this adaptation in my area.
I thing you're reading too much into it. Believe me, I'm very familiar with the absorption curve of chloropyll. But when we are talking about the difference between 10,000K and 5,000K lights, you aren't going to see any difference in growth in the plants. The intensity of the output is going to have a greater influence. The importance of light towards the blue end in aquaria has more to do with the properties of water as a light filter than anything else. Also, don't confuse color temperature with the color of the spectrum. The color temperature is simply a comparison with the color of a piece of platinum heated to a certain temp. At 5000K platinum glows white. Lower temps glow yellow, orange, or red. And higher temps glow blue. It doesn't really tell you the spectral curve of the output although as you would expect, high color temps will lean heavy toward the blue end and lower temps will lean heavy toward the red end. In theory you could have a bad plant light with a big green spike and a red spike that yielded a color temp of 5000K but in practice I doubt this is possible. Bottom line is that within the bulbs we use in vivaria, color temp is an aesthetic choice. If you want the best for the plants, choose the one with the highest photosythetically active radiation (PAR) which means get the brightest lights. If you are really worried about the color of light being provided to the plants, the color temp is not the index to use. You need to actually get the manufacturers data on spectral output.Mantellaprince20 said:Actually, color temp is very important in plants. Green and yellow are reflected by the leaves, therefore, are of no benefit to the plants. Blues and reds are the most important colors of the light spectrum that plants utilize for photosyhthesis. The more efficient the plant can produce food via its chloroplast, the faster it can grow, and teh better it will look. It most definitely is NOT a myth. I haven't quite gotten to this point in my plant biology class yet, but when I do I will know a little more. Here is a website you can check out that talks a little bit a bout it. http://deseretnews.com/dn/view/0,1249,600106092,00.html
For what it's worth, I like the 5000K - 5500K bulbs best but the UVB producing CF bulbs are 6700K so I've been switching over. Although I still like the 5500K slightly better, the difference isn't enough to make me switch back. If 6500K are a lot cheaper, it's a no brainer for me.Schism said:Thanks guys.
I'm thinking I might go cheap with the 6500k's. its just not enough difference that I can see to make the price almost double. ...
What is that? I have a 15H that is unoccupied, and "growing in" I have a 65W-5000k compact bulb, driven by a 96W ballast over one end. The tank gets up into the upper 80's (don't worry, no frogs are going in there till I put a smaller light on...I like to ZAP my new tanks with light to jump start them so to speak.)bbrock said:Also, there are limits to the rate of photosynthesis. Have you gotten to photoinhibition yet? This can be very important in warm vivaria.
Not the same thing, but if you are seeing leaf scorching, then most likely it is from photoinhibition. Photoinhibition happens when a leaf heats up beyond the limits of chlorophyl to remain active. When that happens, photosynthesis shuts down, when photosynthesis shuts down, the visible light that would have triggered photosynthesis gets absorbed by the leaf and converted to heat which compounds the problem. Leaves heated up too much will scorch. When people seeing blanching or scorching of plants, especially close to the lights, they sometimes assume that the problem is too much light. In reality it is hard to provide too much light for plants with current lamp tecnologies and the problem is really too much heat. If the leaf temperatures could be reduced, the plants would almost certainly be able to process the levels of light hitting them just fine.Dancing frogs said:What is that? I have a 15H that is unoccupied, and "growing in" I have a 65W-5000k compact bulb, driven by a 96W ballast over one end. The tank gets up into the upper 80's (don't worry, no frogs are going in there till I put a smaller light on...I like to ZAP my new tanks with light to jump start them so to speak.)
Anyways, the Java moss is growing real well, but the fittonia is hardly growing at all, and I have one viney plant (sorry, I forget the name) that has puple undersided leaves, which is hardly growing, but showing awesome coloration.
Does this sound like what you mentioned?