light for corals

[BA]

Will these corals go ghood under 175watt MH in a 30 gallon, opr should they go under my 400 Watt instead???

Insane Green candy cane (caulastrea)
Brown Montipora digita
green blastomussa Merletti
yellow/green acro milli

3 different tree leathers (sinularia)
a frag of regular caulastrea
another frag of Insane green caulastrea
a frag or grn blastomussa Merletti
a frog of cult coral

[JimD]

Those corals will be fine with that lighting as long as its not 20K. Most of those are LPS and dont require intense lighting. Id bring the Milli up a bit along with the Digi. Im not sure about the frog of colt coral... :-)

[Ram_Puppy]

excuse my inexperience, but I thought color temp (10K, 20K) witht he exception of 20K's providing some actinic spectrum, were more for our eyes than the coral, and the effect I have heard about, is that a 10K will make it grow faster while a 20K will give it better coloration... (or is it the other way around?)

Just wondering becuase I just just convinced myself to try and find a cube tank between 50 and 90 gallons and was planning on slapping a 400w 20K xm on it with a backup of 24" VHO's running half actinic and half 10K... (I have a 175 watt 10K xm right now, and I think it makes the tank look yellow. I have heard that Xm 20K's are more like a 13 or 15K in their 'display')

Thanks, and edumacation, is as always, highly appreciated.

[brewercm]

I think what JimD was meaning by the 20K is that the PAR rating of a 20K for a 175 watt bulb may not be enough lite for some of the corals. If you've ever seen a 20K next to the same wattage 10K you'd see a massive difference in brightness.

[Ram_Puppy]

ahhhh! enlightenment! No pun intended.

[JimD]

I think what JimD was meaning by the 20K is that the PAR rating of a 20K for a 175 watt bulb may not be enough lite for some of the corals. If you've ever seen a 20K next to the same wattage 10K you'd see a massive difference in brightness.

Exactly, thanks brewer, and sorry ram, I should have been more detailed in my post.

[GaryP]

IMO, the lower the temp., the faster they will grow. My corals grew FAST under 6.5K, but then they didn't have a lot of color even with actinic VHO supplemental lighting. 10K is usually considered a good compromise between color and growth. For the record, I'm running 12K now, but will probably go back to 10K on the next bulb change.

Gary

[JimD]

Gary, which 12k lamp are you running?

[GaryP]

Jim,

They are BlueLines. I went from Iwaki 6.5 K to these Bluelines. I guess that is from one extreme to another. They were advertised as a "blue" 10K but I later realized they are more like a 12K. They do give great color but I think I will try going to a true 10K next time to see if there is a difference in gorwth rates. Its not like I am not getting good growth with them, but no where near as much as I had with the Iwaki's.

Gary

[JimD]

Tellya what, if you want growth and good color, with minimal supplimentation, try the XM 10K's, those suckers are BRIGHT! I had one over my tank and it was too much. I replaced it with a 250W and its perfect. Ive got a brand new 400W Ushio 10K you can try if ya want. I just bought the thing and decided I like the 250W XM better..

[GaryP]

Jim,

I was planning on going with the XM's after hearing their praises sung here and elsewhere. I have a few months to go before my next scheduled bulb changes. I'm actually changing my reflectors today. That's my highest priority right now, but thanks for the offer Jim.

Gary