Metal halide
- Thread starter Andrew_bram
- Start date
It depends. Radium 20k is more like a 14k than most 20k bulbs are. Phoenix 14K and Radium 20k are VERY similar IMO. Some 20k look like windex and some have crisp white water with lots of pop. I would caution you to think of K ratings as more of a suggestion than an absolute. 
Generally speaking, the lower K the light (closer to sunlight at about 5500-6500k), the better growth and actual colors will be rendered in the coral. ...but those low K bulbs are terrible at illumination. This is why people swear that their 6500k Halide with VHO Super Actinics was the best color ever - great at rendering with the daylight and also great illumination with the Super Actinics. 14 and 20k bulbs are a compromise. They can both color and illuminate in one package, but the growth is a bit slower and some of the pinks and reds are not as good with 20k as they are with 14k. There are bulbs like 10k and 12.5k that are more of a crisp white without too much blue, but they really do pop coral.
While we are on Halides, there is k and there is K. k means thousands... like in 6.5k bulb meaning 6500. K is for Kelvin or the temperature/color of the bulb. Most people mix them up, but if you are reading specs and articles, it might matter. Technically, a 6.5kK bulb is right - 6.5 thousand Kelvin... but people usually only use one K.
Generally speaking, the lower K the light (closer to sunlight at about 5500-6500k), the better growth and actual colors will be rendered in the coral. ...but those low K bulbs are terrible at illumination. This is why people swear that their 6500k Halide with VHO Super Actinics was the best color ever - great at rendering with the daylight and also great illumination with the Super Actinics. 14 and 20k bulbs are a compromise. They can both color and illuminate in one package, but the growth is a bit slower and some of the pinks and reds are not as good with 20k as they are with 14k. There are bulbs like 10k and 12.5k that are more of a crisp white without too much blue, but they really do pop coral.
While we are on Halides, there is k and there is K. k means thousands... like in 6.5k bulb meaning 6500. K is for Kelvin or the temperature/color of the bulb. Most people mix them up, but if you are reading specs and articles, it might matter. Technically, a 6.5kK bulb is right - 6.5 thousand Kelvin... but people usually only use one K.
So if I prefer a bluer overall appearance I wouldn't necessarily be punished for going 20k in terms of coral growth....maybe something like these Hamilton 20k's that are on sale this weekend?
No punishment. Even a 20k Halide will outgrow 8 bulb T5 setups and every LED on the market. Even if 6500k will have faster growth, growth is not everything... enjoying your stuff is better. Besides, it sucks to butcher colonies when they are growing together, so I like to keep this as slow as I can. Even under 14k lighting, I can fill a tank with 3/4 inch acropora frags and in three years have wall to wall colonies.
The new Hamilton 20k was modeled after the 20k Radium, but to run on non-HQI ballasts. It should have a very similar look, but lower output since it is driven at 250w with ANSI m58 or Electronic ballast instead of at 330w with m80 ballast.
Like I said, if you want to stop by, I have a bunch that we can look at. I saw that Elite has some MH back on their tanks too... not sure how long that has been, but they look nice.
The new Hamilton 20k was modeled after the 20k Radium, but to run on non-HQI ballasts. It should have a very similar look, but lower output since it is driven at 250w with ANSI m58 or Electronic ballast instead of at 330w with m80 ballast.
Like I said, if you want to stop by, I have a bunch that we can look at. I saw that Elite has some MH back on their tanks too... not sure how long that has been, but they look nice.
Maybe @Andrew_bram and I need to take a road trip to Longmont!
Sunday, Monday, or Wednesday? Any of that work for @jda123 and @Andrew_bram ?
