[maroonclown]

I have a 100 gal reef with 2 175 watt metal halide bulbs and 4 40 watt NO flourscents. I'm at the point where I need to replace my metal halides. With all the choices in different "k's" for the bulbs I have no idea which is better. I've been thinking somewhere between 10000K and 20000k. Any advice?

[zhenya]

Hi maroonclown and Welcome to Reefland!

Here's a thread started by JB NY a little while ago where he had run some tests on the 250W MH bulbs but the wattage doesn't really matter I think.
There is some very nice pics and some very interesting data as well on different bulbs.
http://reefcentral.com/forums/showth...hreadid=254667

Also, I think it would depend a lot on what exactly you are trying to keep in your tank.

[maroonclown]

I forgot to tell which critters I have. I have colt coral and toad stool leather coral of the soft variety, a pearl and favia moon of the Lps stoney, a crocea clam, goniporia, a carpet anemone and long tenticle anemone. I also have a faxface, purple tang and a maroon clown.

[zhenya]

What color temperature are your present bulbs? From what you listed as far as your critters I'd probably go with the 10K bulbs. Also, it is very personal thing as far as how your tank appears to look and there is no two opinons are alike when it comes to light discussions

[Poseidon]

I have the AB10K bulbs and really like them. I'm due for bulb replacement now, and thanks to Zhenya and his testing, I'm going to use the CV10K this time around. Make sure to browse through the thread over in Reef central, it HAS TONS of info in it JB NY has done us all a TREMENDOUS service comparing all those bulbs and ballasts!!!

[reewik]

I am running the XM 10,000k. it has done very well so far. I have had it about a month. I have seen some great color shifts and it is a very bright white bulb (if you like that). I run it on a Custom Sealife Ballast.

[maroonclown]

Thanks for all your help folks. Funny thing is that when I went to my LFS all they had was one 20000K bulb. Seeing it side by side with my one bulb that I didn't get to replace shows an incredible difference. The critters seem to be happy with it. In fact they all seem alittle more lively, corals and fish included. I do not know if this is from the fact that it was time to change bulbs, or what. As for the colour of the 20000K, it is a clear white with a hint of ice blue in the light, making all the colours in my tank pop.

[reewik]

Ouch, I bet you paid a wopping 100.00 bucks for that bulb. In the future when in need of a bulb I suggest online. I paid 65.00 for my bulb and I have seen several MH bulbs for around 75.00. I should have included this before. Sorry Maroonclown.