What is the best 400w bulb available for acropora

[ReefRockerLive]

I am currently using one 15k XM and 20k XM 400w MH bulbs. Both bulbs are around 7-8 months old and I am looking to try out another bulb. I have not seen much growth from these lights, could it be possible that my bulbs are getting old or can it be something in my water?

These lights are under a 75g tank. Would it also be that I have too much light for acros? The lights are 18" from the water. I was looking at the Giesseman 13000K Megachrome are they worth all that money?

How well does the Reeflux 12k bulbs work on a magnetic ballast? Those bulbs are within my price range too.

What 400w MH bulbs would you reefers recommend for the most par and growth for acropora?

Thanks

 

[cediss]

Your problem is that you mounted the bulb under the tank. They need to be mounted above the tank so the corals get light! LOL.

All joking aside, are you using single or double ended. I think that makes a difference. Many have done research which shows lower Kalvin tends to produce faster growth. Beyond that I wonder what people recommend?

 

[ReefRockerLive]

I am running Single Ended bulbs

 

[Gary Majchrzak]

Is this a recent pic of your aquarium?

 

[ReefRockerLive]

Yes it is

 

[Gary Majchrzak]

Re: What is the best 400w bulb available for acropora

<a href=showthread.php?s=&postid=7456122#post7456122 target=_blank>Originally posted</a> by ReefRockerLive
I have not seen much growth from these lights, could it be possible that my bulbs are getting old or can it be something in my water?

It might be both. Do you have a Goniopora in the same aquarium as your Acros? Any Fungiids? (Both are highly toxic).
Are you aware of the possibility of allelopathy (chemical warfare) between corals?
Make sure to do regular partial water changes, continuously run a small amount of (fresh) carbon and run a good skimmer.
I have a feeling that your lighting is less to blame than you might think. Nice looking aquarium, BTW.

 

[cediss]

Looks good Gary. My limited knowledge on this topic would lead me to say that your less than desirable growth rates are because of the lower Kalvin bulbs. But I don't know what SPS you have. In the piture I see a fare number of LPS which of course tend to grow much slower. I personally like both the bright appearance and colors from 10K range, and look of water and certain corals with the 14-20K range. So what I am doing is combining these. I am using 14K on my 400 watters and 10K on my 175 watters. This way I stagger and overlap the photoperiod to combine the best of both worlds. This works best IMO when the two different color bulbs are placed within a few inches of each other. That way you don't get the two tone appearance that many distaste when both bulbs are on at the same time. As for single bulbs, I prefer the look of 14K bulbs, but don't have experience with a lot of different manufacturers. I like the look of CoralVue 14K 400Watt and they are priced well. But I can't tell you about growth rate under thisbulb because I have only been running it for about 2-3 months. It is also running part of the day with a 175 w 10K. Previously I used Coralvue 10K 400Watt which gives good growth and color, but with your use of 15 and 20K, you would have a hard time adjusting to a 10K.

 

[cediss]

I am aware of allelopathy (chemical warfare), but have never heard of the goniopora or fungiids having this effect on acro growth! Something to look into if this is true. Gary, any sources to point me to look into this more?