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Are actinics necessary for growth?
- Thread starter magic
- Start date
Bob,
I honestly think to get good growth you need to keep water conditions in the correct zones (proper Ph, Alk, Calcium, Mag, SG, etc...) IMO the light spectrum is just a small part of good growth.
That being said, I think the lower Kelvin bulbs 6500K and 10000K are better for growth.
I honestly think to get good growth you need to keep water conditions in the correct zones (proper Ph, Alk, Calcium, Mag, SG, etc...) IMO the light spectrum is just a small part of good growth.
That being said, I think the lower Kelvin bulbs 6500K and 10000K are better for growth.
I read that book by Anthony Calfo, Coral Propagation somethingorother. In that book, he states that the most significant growth is achieved by utilizing 6500k mh. I also saw him at several seminars and spoke to him on the phone, great guy. Anyway, he also states that the most fabulous shades of brown will also be achieved with 6500k. You will have BIG BROWN corals. But if you switch to actinics and 10,000k or higher, everything will color up, but grow slow. So then he says that he makes them grow like crazy then switches lighting to color them, then he sells them. But as Mike says, water conditions set precedent.
I'm not sure it's an exact science. But in theory that's what "should" happen.
To my (little) knowledge Actinics ARE just for show, and have no benefits to the corals. 
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Wendy
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Wendy
For the most part I typically agree 99%+ with Anthony (of all authors in the trade). His book on coral propagation is a really good book that's different from most. It's got info in it you won't find anywhere else.
I myself wouldn't go as far a saying the "blue" spectrum isn't needed. Some corals get more blue spectrum then any other. They also happen to grow much slower then most also. To me water chemistry is king, followed by flow then light in that order.
I think most people would have a hard time going with 6.5K lamps as their main lamps. If you don't have your nutrients very well under control you will have algae growth like you won't believe. Any bit of silica in the water and you'll have diatoms like crazy. The 6.5K lamps do grow things fast but not just your corals.
I think the old saying "10K to grow, 20K to show" is pretty accurate and would serve most people pretty well. I also don't think many people would really care for the look of their tank using only 6.5K lamps. Many corals especially SPS will be much browner and look much more similar to what you would find in the ocean compared to the "pretty colors" you see online and people's tanks running higher K lamps.
Now stepping a side from the main tank and going to a prop tank is another story. I think most people would do better by leaning on the 6.5K/8K lamps for pure growth. Once you've grown them to the size you want/need you can move them into your display where they will gradually color up more. I myself use 6.5K lamps over my prop tanks with no blues at all.
I think if I were to ever start over I'd go with a T5/6 setup with 6 or 8 lamps. I could start it out with all low K lamps and as growth is achieved start to change out the lamps every month to add more color and allow the corals to gradually get a spectrum shift with a little more blue at a time. This could be from switching out 6.5K to either 10K or 14K or to true blue bulbs. Either way it would allow for a more gradual shift in spectrum compared to just moving them into another system.
Anyway, getting back to magic's question. Yes you would get more growth but you might not like the coloring of the corals at first or the way your tank looks.
Carlo
I myself wouldn't go as far a saying the "blue" spectrum isn't needed. Some corals get more blue spectrum then any other. They also happen to grow much slower then most also. To me water chemistry is king, followed by flow then light in that order.
I think most people would have a hard time going with 6.5K lamps as their main lamps. If you don't have your nutrients very well under control you will have algae growth like you won't believe. Any bit of silica in the water and you'll have diatoms like crazy. The 6.5K lamps do grow things fast but not just your corals.
I think the old saying "10K to grow, 20K to show" is pretty accurate and would serve most people pretty well. I also don't think many people would really care for the look of their tank using only 6.5K lamps. Many corals especially SPS will be much browner and look much more similar to what you would find in the ocean compared to the "pretty colors" you see online and people's tanks running higher K lamps.
Now stepping a side from the main tank and going to a prop tank is another story. I think most people would do better by leaning on the 6.5K/8K lamps for pure growth. Once you've grown them to the size you want/need you can move them into your display where they will gradually color up more. I myself use 6.5K lamps over my prop tanks with no blues at all.
I think if I were to ever start over I'd go with a T5/6 setup with 6 or 8 lamps. I could start it out with all low K lamps and as growth is achieved start to change out the lamps every month to add more color and allow the corals to gradually get a spectrum shift with a little more blue at a time. This could be from switching out 6.5K to either 10K or 14K or to true blue bulbs. Either way it would allow for a more gradual shift in spectrum compared to just moving them into another system.
Anyway, getting back to magic's question. Yes you would get more growth but you might not like the coloring of the corals at first or the way your tank looks.
Carlo
magic said:
Your T5s wouldn't be throwing nearly the light that your MHs are, and so therefore you're not going to be sending enough 6700 light to really change the equation much. Now turn it around and use 6500MHs and blue plus actinics and you might see something. This is actually the theory behind why we run 10K XMs in between our 12K reflux bulbs (on different non-overlapping schedules). To add light in a spectrum closer to the growth spectrum. I might try 6500s in there next (though the color on those might be enough for me to change back to 10Ks).