Difference between 420 vs 460 actinic bulbs?

So maybe a newbie question but was just curious what the difference is between a 420nm bulb vs a 460nm bulb? Does one offer more growth for your corals? Thanks

So a 420 really isn't 'good' to have it just makes the tank look nice?  If I put a PC with both 420 and 460 would I get good growth?

420 is more for a freshwater aquarium as it uses more red spectrum than the blue that why it looks pinkish

whoops my mistake thx for correcting me

Thanks for the info. So have done some searching but so far been unable to turn up a chart or anything like that has all the different color temps and the main color they will put off. Anybody have anything like that or somewhere I can look? Hope this makes sense basically looking for something that says a 20,000K bulb will put off more ....... a 10,000k bulb will put off more ......... Hopefully that helps. Thanks

Lewy wrote: I like the idea of a fuller spectrum but where I have a small aquarium, its a 12 gallon eclipse I am limited on space.  The hood I have can only hold one 13 watt PC and I found a site that sells what I hope is the correct bulb but they only offer a "White/White" and a "Blue/Blue".  The maker of the hood offers a bulb but it only puts off 5500 K.  The lights I orderd claim to put off in the white 10,000 K and the blue claims 420/460.  I orderd both so I can try the out.  Which should I use?

Too late but there are two manufacturers that make better color popping PC tubes. The growth is good too. Helios, available at Fish4U (special order from local supplier Blue Sky Pet Supply which has all sizes, 9W to 96W, currently in stock) and UV Lighting, available at Reefgeek.com

Begging your forgiveness, but a 13 W PC is not much light. It will not offer much in the way of growth and only a little in the way of illumination. If it were me, I'd modify it to take a larger PC tube or put the tank in the window to capture the enormous power of sunlight.

Below is what the tube I was speaking of looks like in action. This was a Helios UltraGrow 36W PC. I would have liked it a little more blue but back then UV Lighting had not yet made its group of color popping PC tubes.



Edited by Mark Peterson - September 02 2010 at 8:57am

Mark, you don't need to beg for forgiveness.  I totally agree I don't have much light.  I actually have the small tank in my kitchen where it gets quite a bit of natural sun light.  Thank you for the advice, I really appreciate it.