10,000K vs. 20,000K Halides

[Electrobes]

Okay as I mentioned before I am in the market for metal halides and after a bunch of research narrowed down a few things. I have a 45G tall, and want to grow any coral, not just specific-only ones. I will most likely be getting a 250 watt metal hallide (still considering which ballast to get, but I will most likely will be going with an XM SE bulb). The part where I get lost is Kelvin rating is best with my set up. I am stuck between either getting a 10,000K bulb or a 20,000K bulb. I ams till considering getting actinics, but I think I will to at LEAST have a dawn and dusk for the tank. But I will most likely need at least two tubes of VHOs to run with a 10000K bulb to have any effect at all on the water and coral color during the day. But with the 20000K I don't see the need for actinics, but I don't think its healthier than the 10000K bulbs. What do you all have/swear by/think? Thanks

[jks1]

agreed, 20k will be more blue, but also keep in mind as you increase k, you decrease intensity. I am not sure of the exact percentage, but 20k bulb will be considerably less intense than a 10k bulb. I plan to go with 10k in my new sps/clam tank

[Electrobes]

yeah thats why I was leaning towards the 10,000K with a VHO tube ot two.

[Hara]

I recently switched from 10k to 20k and the corals are responding quite positively to the change. I am seeing tons new growth where before the growth had stagnated. My clams are thrilled with the change as well.

[jamal-188]

Hara, even with some kind of actinic support with 10,000K you think 20,000K is better for growth? I was going to go w/ 20,000K and not actinics but decided on 10,000 to make sure the intensity woudl be enough and now I'm goning to buy some t5 actinics.

[Hara]

I have actinic support. My system is 3 250 watt HQI with pc actinics. Yes, I am saying the growth has increased.

[jcb19742003]

from info i have read maybe the use of 14 k bulbs will be the best choice i have a 75 gal and i want to use metal hallides and i was going to use the pennants and the 14 k bulbs will give you a happy medium. just a thought

[Biggen]

Jcb,

I had Hamilton 14K's for about a month and changed it out for their 20K version. The 14K's just weren't "blue" enough for me. I am very happy with their 20K. Nice clean looking blue hue. Not too much and not too little. I love them.

It really depends on personal preference. Some people will tell you that using only 20K bulbs will wash your tanks colors out. That doesn't happen to me. In fact, it appears to be the exact opposite. I will never go with anything less than a 14K bulb.